The orig_a0 is missing in struct user_regs_struct of riscv, and there is no way to add it without breaking UAPI. (See Link tag below)
Like NT_ARM_SYSTEM_CALL do, we add a new regset name NT_RISCV_ORIG_A0 to access original a0 register from userspace via ptrace API.
Link: https://lore.kernel.org/all/59505464-c84a-403d-972f-d4b2055eeaac@gmail.com/
Signed-off-by: Celeste Liu uwu@coelacanthus.name --- Changes in v2: - Fix integer width. - Add selftest. - Link to v1: https://lore.kernel.org/r/20241201-riscv-new-regset-v1-1-c83c58abcc7b@coelac...
--- Celeste Liu (1): riscv/ptrace: add new regset to access original a0 register
Charlie Jenkins (1): riscv: selftests: Add a ptrace test to verify syscall parameter modification
arch/riscv/kernel/ptrace.c | 32 +++++++ include/uapi/linux/elf.h | 1 + tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 5 files changed, 172 insertions(+), 1 deletion(-) --- base-commit: 0e287d31b62bb53ad81d5e59778384a40f8b6f56 change-id: 20241201-riscv-new-regset-d529b952ad0d
Best regards,
The orig_a0 is missing in struct user_regs_struct of riscv, and there is no way to add it without breaking UAPI. (See Link tag below)
Like NT_ARM_SYSTEM_CALL do, we add a new regset name NT_RISCV_ORIG_A0 to access original a0 register from userspace via ptrace API.
Link: https://lore.kernel.org/all/59505464-c84a-403d-972f-d4b2055eeaac@gmail.com/ Cc: stable@vger.kernel.org Signed-off-by: Celeste Liu uwu@coelacanthus.name --- arch/riscv/kernel/ptrace.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 2 files changed, 33 insertions(+)
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index ea67e9fb7a583683b922fe2c017ea61f3bc848db..18ce07ffb27bb1180667769eed800f6fdf96c083 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -31,6 +31,7 @@ enum riscv_regset { #ifdef CONFIG_RISCV_ISA_SUPM REGSET_TAGGED_ADDR_CTRL, #endif + REGSET_ORIG_A0, };
static int riscv_gpr_get(struct task_struct *target, @@ -184,6 +185,29 @@ static int tagged_addr_ctrl_set(struct task_struct *target, } #endif
+static int riscv_orig_a0_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to) +{ + return membuf_store(&to, task_pt_regs(target)->orig_a0); +} + +static int riscv_orig_a0_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + unsigned long orig_a0 = task_pt_regs(target)->orig_a0; + int ret; + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &orig_a0, 0, -1); + if (ret) + return ret; + + task_pt_regs(target)->orig_a0 = orig_a0; + return ret; +} + static const struct user_regset riscv_user_regset[] = { [REGSET_X] = { .core_note_type = NT_PRSTATUS, @@ -224,6 +248,14 @@ static const struct user_regset riscv_user_regset[] = { .set = tagged_addr_ctrl_set, }, #endif + [REGSET_ORIG_A0] = { + .core_note_type = NT_RISCV_ORIG_A0, + .n = 1, + .size = sizeof(elf_greg_t), + .align = sizeof(elf_greg_t), + .regset_get = riscv_orig_a0_get, + .set = riscv_orig_a0_set, + }, };
static const struct user_regset_view riscv_user_native_view = { diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index b44069d29cecc0f9de90ee66bfffd2137f4275a8..390060229601631da2fb27030d9fa2142e676c14 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -452,6 +452,7 @@ typedef struct elf64_shdr { #define NT_RISCV_CSR 0x900 /* RISC-V Control and Status Registers */ #define NT_RISCV_VECTOR 0x901 /* RISC-V vector registers */ #define NT_RISCV_TAGGED_ADDR_CTRL 0x902 /* RISC-V tagged address control (prctl()) */ +#define NT_RISCV_ORIG_A0 0x903 /* RISC-V original a0 register */ #define NT_LOONGARCH_CPUCFG 0xa00 /* LoongArch CPU config registers */ #define NT_LOONGARCH_CSR 0xa01 /* LoongArch control and status registers */ #define NT_LOONGARCH_LSX 0xa02 /* LoongArch Loongson SIMD Extension registers */
Celeste Liu uwu@coelacanthus.name writes:
The orig_a0 is missing in struct user_regs_struct of riscv, and there is no way to add it without breaking UAPI. (See Link tag below)
Like NT_ARM_SYSTEM_CALL do, we add a new regset name NT_RISCV_ORIG_A0 to access original a0 register from userspace via ptrace API.
Link: https://lore.kernel.org/all/59505464-c84a-403d-972f-d4b2055eeaac@gmail.com/ Cc: stable@vger.kernel.org Signed-off-by: Celeste Liu uwu@coelacanthus.name
arch/riscv/kernel/ptrace.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 2 files changed, 33 insertions(+)
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index ea67e9fb7a583683b922fe2c017ea61f3bc848db..18ce07ffb27bb1180667769eed800f6fdf96c083 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -31,6 +31,7 @@ enum riscv_regset { #ifdef CONFIG_RISCV_ISA_SUPM REGSET_TAGGED_ADDR_CTRL, #endif
- REGSET_ORIG_A0,
}; static int riscv_gpr_get(struct task_struct *target, @@ -184,6 +185,29 @@ static int tagged_addr_ctrl_set(struct task_struct *target, } #endif +static int riscv_orig_a0_get(struct task_struct *target,
const struct user_regset *regset,struct membuf to)+{
- return membuf_store(&to, task_pt_regs(target)->orig_a0);
+}
+static int riscv_orig_a0_set(struct task_struct *target,
const struct user_regset *regset,unsigned int pos, unsigned int count,const void *kbuf, const void __user *ubuf)+{
- unsigned long orig_a0 = task_pt_regs(target)->orig_a0;
- int ret;
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &orig_a0, 0, -1);
- if (ret)
return ret;- task_pt_regs(target)->orig_a0 = orig_a0;
- return ret;
Nit: Could be return 0, for readability.
Regardless, Reviewed-by: Björn Töpel bjorn@rivosinc.com
Hi Celeste,
On 03/12/2024 10:30, Celeste Liu wrote:
The orig_a0 is missing in struct user_regs_struct of riscv, and there is no way to add it without breaking UAPI. (See Link tag below)
Like NT_ARM_SYSTEM_CALL do, we add a new regset name NT_RISCV_ORIG_A0 to access original a0 register from userspace via ptrace API.
Link: https://lore.kernel.org/all/59505464-c84a-403d-972f-d4b2055eeaac@gmail.com/ Cc: stable@vger.kernel.org Signed-off-by: Celeste Liu uwu@coelacanthus.name
arch/riscv/kernel/ptrace.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 2 files changed, 33 insertions(+)
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index ea67e9fb7a583683b922fe2c017ea61f3bc848db..18ce07ffb27bb1180667769eed800f6fdf96c083 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -31,6 +31,7 @@ enum riscv_regset { #ifdef CONFIG_RISCV_ISA_SUPM REGSET_TAGGED_ADDR_CTRL, #endif
- REGSET_ORIG_A0, };
static int riscv_gpr_get(struct task_struct *target, @@ -184,6 +185,29 @@ static int tagged_addr_ctrl_set(struct task_struct *target, } #endif +static int riscv_orig_a0_get(struct task_struct *target,
const struct user_regset *regset,struct membuf to)+{
- return membuf_store(&to, task_pt_regs(target)->orig_a0);
+}
+static int riscv_orig_a0_set(struct task_struct *target,
const struct user_regset *regset,unsigned int pos, unsigned int count,const void *kbuf, const void __user *ubuf)+{
- unsigned long orig_a0 = task_pt_regs(target)->orig_a0;
- int ret;
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &orig_a0, 0, -1);
- if (ret)
return ret;- task_pt_regs(target)->orig_a0 = orig_a0;
- return ret;
+}
- static const struct user_regset riscv_user_regset[] = { [REGSET_X] = { .core_note_type = NT_PRSTATUS,
@@ -224,6 +248,14 @@ static const struct user_regset riscv_user_regset[] = { .set = tagged_addr_ctrl_set, }, #endif
- [REGSET_ORIG_A0] = {
.core_note_type = NT_RISCV_ORIG_A0,.n = 1,.size = sizeof(elf_greg_t),.align = sizeof(elf_greg_t),.regset_get = riscv_orig_a0_get,.set = riscv_orig_a0_set,- }, };
static const struct user_regset_view riscv_user_native_view = { diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index b44069d29cecc0f9de90ee66bfffd2137f4275a8..390060229601631da2fb27030d9fa2142e676c14 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -452,6 +452,7 @@ typedef struct elf64_shdr { #define NT_RISCV_CSR 0x900 /* RISC-V Control and Status Registers */ #define NT_RISCV_VECTOR 0x901 /* RISC-V vector registers */ #define NT_RISCV_TAGGED_ADDR_CTRL 0x902 /* RISC-V tagged address control (prctl()) */ +#define NT_RISCV_ORIG_A0 0x903 /* RISC-V original a0 register */ #define NT_LOONGARCH_CPUCFG 0xa00 /* LoongArch CPU config registers */ #define NT_LOONGARCH_CSR 0xa01 /* LoongArch control and status registers */ #define NT_LOONGARCH_LSX 0xa02 /* LoongArch Loongson SIMD Extension registers */
Do you know how far this should be backported? Does the following fixes tag make sense?
Fixes: e2c0cdfba7f6 ("RISC-V: User-facing API")
Thanks,
Alex
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com --- tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 3 files changed, 139 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/riscv/abi/.gitignore b/tools/testing/selftests/riscv/abi/.gitignore index b38358f91c4d2240ae64892871d9ca98bda1ae58..378c605919a3b3d58eec2701eb7af430cfe315d6 100644 --- a/tools/testing/selftests/riscv/abi/.gitignore +++ b/tools/testing/selftests/riscv/abi/.gitignore @@ -1 +1,2 @@ pointer_masking +ptrace diff --git a/tools/testing/selftests/riscv/abi/Makefile b/tools/testing/selftests/riscv/abi/Makefile index ed82ff9c664e7eb3f760cbab81fb957ff72579c5..3f74d059dfdcbce4d45d8ff618781ccea1419061 100644 --- a/tools/testing/selftests/riscv/abi/Makefile +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -2,9 +2,12 @@
CFLAGS += -I$(top_srcdir)/tools/include
-TEST_GEN_PROGS := pointer_masking +TEST_GEN_PROGS := pointer_masking ptrace
include ../../lib.mk
$(OUTPUT)/pointer_masking: pointer_masking.c $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^ + +$(OUTPUT)/ptrace: ptrace.c + $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^ diff --git a/tools/testing/selftests/riscv/abi/ptrace.c b/tools/testing/selftests/riscv/abi/ptrace.c new file mode 100644 index 0000000000000000000000000000000000000000..d192764b428d1f1c442f3957c6fedeb01a48d556 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/ptrace.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/stat.h> +#include <sys/user.h> +#include <sys/wait.h> +#include <sys/uio.h> +#include <linux/elf.h> +#include <linux/unistd.h> +#include <asm/ptrace.h> + +#include "../../kselftest_harness.h" + +#define ORIG_A0_MODIFY 0x01 +#define A0_MODIFY 0x02 +#define A0_OLD 0x03 +#define A0_NEW 0x04 + +#define perr_and_exit(fmt, ...) \ + ({ \ + char buf[256]; \ + snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \ + __func__, __LINE__, ##__VA_ARGS__); \ + perror(buf); \ + exit(-1); \ + }) + +static inline void resume_and_wait_tracee(pid_t pid, int flag) +{ + int status; + + if (ptrace(flag, pid, 0, 0)) + perr_and_exit("failed to resume the tracee %d\n", pid); + + if (waitpid(pid, &status, 0) != pid) + perr_and_exit("failed to wait for the tracee %d\n", pid); +} + +static void ptrace_test(int opt, int *result) +{ + int status; + pid_t pid; + struct user_regs_struct regs; + struct iovec iov = { + .iov_base = ®s, + .iov_len = sizeof(regs), + }; + + unsigned long orig_a0; + struct iovec a0_iov = { + .iov_base = &orig_a0, + .iov_len = sizeof(orig_a0), + }; + + pid = fork(); + if (pid == 0) { + /* Mark oneself being traced */ + long val = ptrace(PTRACE_TRACEME, 0, 0, 0); + + if (val) + perr_and_exit("failed to request for tracer to trace me: %ld\n", val); + + kill(getpid(), SIGSTOP); + + /* Perform exit syscall that will be intercepted */ + exit(A0_OLD); + } + + if (pid < 0) + exit(1); + + if (waitpid(pid, &status, 0) != pid) + perr_and_exit("failed to wait for the tracee %d\n", pid); + + /* Stop at the entry point of the syscall */ + resume_and_wait_tracee(pid, PTRACE_SYSCALL); + + /* Check tracee regs before the syscall */ + if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov)) + perr_and_exit("failed to get tracee registers\n"); + if (ptrace(PTRACE_GETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov)) + perr_and_exit("failed to get tracee registers\n"); + if (orig_a0 != A0_OLD) + perr_and_exit("unexpected orig_a0: 0x%lx\n", orig_a0); + + /* Modify a0/orig_a0 for the syscall */ + switch (opt) { + case A0_MODIFY: + regs.a0 = A0_NEW; + break; + case ORIG_A0_MODIFY: + orig_a0 = A0_NEW; + break; + } + + if (ptrace(PTRACE_SETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov)) + perr_and_exit("failed to set tracee registers\n"); + + /* Resume the tracee */ + ptrace(PTRACE_CONT, pid, 0, 0); + if (waitpid(pid, &status, 0) != pid) + perr_and_exit("failed to wait for the tracee\n"); + + *result = WEXITSTATUS(status); +} + +TEST(ptrace_modify_a0) +{ + int result; + + ptrace_test(A0_MODIFY, &result); + + /* The modification of a0 cannot affect the first argument of the syscall */ + EXPECT_EQ(A0_OLD, result); +} + +TEST(ptrace_modify_orig_a0) +{ + int result; + + ptrace_test(ORIG_A0_MODIFY, &result); + + /* Only modify orig_a0 to change the first argument of the syscall */ + EXPECT_EQ(A0_NEW, result); +} + +TEST_HARNESS_MAIN
Celeste Liu uwu@coelacanthus.name writes:
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com
Nice with a selftest! (Don't think the Cc: stable applies... ;-))
Reviewed-by: Björn Töpel bjorn@rivosinc.com
On Tue, Dec 03, 2024 at 05:30:05PM +0800, Celeste Liu wrote:
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com
tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 3 files changed, 139 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/riscv/abi/.gitignore b/tools/testing/selftests/riscv/abi/.gitignore index b38358f91c4d2240ae64892871d9ca98bda1ae58..378c605919a3b3d58eec2701eb7af430cfe315d6 100644 --- a/tools/testing/selftests/riscv/abi/.gitignore +++ b/tools/testing/selftests/riscv/abi/.gitignore @@ -1 +1,2 @@ pointer_masking +ptrace diff --git a/tools/testing/selftests/riscv/abi/Makefile b/tools/testing/selftests/riscv/abi/Makefile index ed82ff9c664e7eb3f760cbab81fb957ff72579c5..3f74d059dfdcbce4d45d8ff618781ccea1419061 100644 --- a/tools/testing/selftests/riscv/abi/Makefile +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -2,9 +2,12 @@ CFLAGS += -I$(top_srcdir)/tools/include -TEST_GEN_PROGS := pointer_masking +TEST_GEN_PROGS := pointer_masking ptrace include ../../lib.mk $(OUTPUT)/pointer_masking: pointer_masking.c $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
+$(OUTPUT)/ptrace: ptrace.c
- $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
diff --git a/tools/testing/selftests/riscv/abi/ptrace.c b/tools/testing/selftests/riscv/abi/ptrace.c new file mode 100644 index 0000000000000000000000000000000000000000..d192764b428d1f1c442f3957c6fedeb01a48d556 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/ptrace.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/stat.h> +#include <sys/user.h> +#include <sys/wait.h> +#include <sys/uio.h> +#include <linux/elf.h> +#include <linux/unistd.h> +#include <asm/ptrace.h>
+#include "../../kselftest_harness.h"
+#define ORIG_A0_MODIFY 0x01 +#define A0_MODIFY 0x02 +#define A0_OLD 0x03 +#define A0_NEW 0x04
Shouldn't A0_OLD and A0_NEW set more bits, since 3 and 4 aren't very unique (we could have those values by accident)? And should we include setting bits over 31 for 64-bit targets?
+#define perr_and_exit(fmt, ...) \
- ({ \
char buf[256]; \snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \__func__, __LINE__, ##__VA_ARGS__); \perror(buf); \exit(-1); \- })
Can we use e.g. ksft_exit_fail_perror() instead? I'd prefer we try to consolidate testing/selftests/riscv/* tests on a common format for errors and exit codes and we're already using other kselftest stuff.
+static inline void resume_and_wait_tracee(pid_t pid, int flag) +{
- int status;
- if (ptrace(flag, pid, 0, 0))
perr_and_exit("failed to resume the tracee %d\n", pid);- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);+}
+static void ptrace_test(int opt, int *result) +{
- int status;
- pid_t pid;
- struct user_regs_struct regs;
- struct iovec iov = {
.iov_base = ®s,.iov_len = sizeof(regs),- };
- unsigned long orig_a0;
- struct iovec a0_iov = {
.iov_base = &orig_a0,.iov_len = sizeof(orig_a0),- };
- pid = fork();
- if (pid == 0) {
/* Mark oneself being traced */long val = ptrace(PTRACE_TRACEME, 0, 0, 0);if (val)perr_and_exit("failed to request for tracer to trace me: %ld\n", val);kill(getpid(), SIGSTOP);/* Perform exit syscall that will be intercepted */exit(A0_OLD);- }
- if (pid < 0)
exit(1);
This unexpected error condition deserves a message, so I'd use ksft_exit_fail_perror() here.
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);- /* Stop at the entry point of the syscall */
- resume_and_wait_tracee(pid, PTRACE_SYSCALL);
- /* Check tracee regs before the syscall */
- if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov))
perr_and_exit("failed to get tracee registers\n");- if (ptrace(PTRACE_GETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to get tracee registers\n");- if (orig_a0 != A0_OLD)
perr_and_exit("unexpected orig_a0: 0x%lx\n", orig_a0);- /* Modify a0/orig_a0 for the syscall */
- switch (opt) {
- case A0_MODIFY:
regs.a0 = A0_NEW;break;- case ORIG_A0_MODIFY:
orig_a0 = A0_NEW;break;- }
- if (ptrace(PTRACE_SETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to set tracee registers\n");- /* Resume the tracee */
- ptrace(PTRACE_CONT, pid, 0, 0);
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee\n");- *result = WEXITSTATUS(status);
+}
+TEST(ptrace_modify_a0) +{
- int result;
- ptrace_test(A0_MODIFY, &result);
- /* The modification of a0 cannot affect the first argument of the syscall */
- EXPECT_EQ(A0_OLD, result);
What about checking that we actually set regs.a0 to A0_NEW? We'd need A0_NEW to be more unique than 4, though.
+}
+TEST(ptrace_modify_orig_a0) +{
- int result;
- ptrace_test(ORIG_A0_MODIFY, &result);
- /* Only modify orig_a0 to change the first argument of the syscall */
If we run ptrace_modify_a0 first then we've already set regs.a0 to A0_NEW and can't check with this test that we don't set it to A0_NEW. We should probably have two different test values, one for regs.a0 and one for orig_a0 and ensure on both tests that we aren't writing both.
- EXPECT_EQ(A0_NEW, result);
+}
+TEST_HARNESS_MAIN
-- 2.47.0
Thanks, drew
On Tue, Dec 03, 2024 at 01:55:07PM +0100, Andrew Jones wrote:
On Tue, Dec 03, 2024 at 05:30:05PM +0800, Celeste Liu wrote:
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com
tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 3 files changed, 139 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/riscv/abi/.gitignore b/tools/testing/selftests/riscv/abi/.gitignore index b38358f91c4d2240ae64892871d9ca98bda1ae58..378c605919a3b3d58eec2701eb7af430cfe315d6 100644 --- a/tools/testing/selftests/riscv/abi/.gitignore +++ b/tools/testing/selftests/riscv/abi/.gitignore @@ -1 +1,2 @@ pointer_masking +ptrace diff --git a/tools/testing/selftests/riscv/abi/Makefile b/tools/testing/selftests/riscv/abi/Makefile index ed82ff9c664e7eb3f760cbab81fb957ff72579c5..3f74d059dfdcbce4d45d8ff618781ccea1419061 100644 --- a/tools/testing/selftests/riscv/abi/Makefile +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -2,9 +2,12 @@ CFLAGS += -I$(top_srcdir)/tools/include -TEST_GEN_PROGS := pointer_masking +TEST_GEN_PROGS := pointer_masking ptrace include ../../lib.mk $(OUTPUT)/pointer_masking: pointer_masking.c $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
+$(OUTPUT)/ptrace: ptrace.c
- $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
diff --git a/tools/testing/selftests/riscv/abi/ptrace.c b/tools/testing/selftests/riscv/abi/ptrace.c new file mode 100644 index 0000000000000000000000000000000000000000..d192764b428d1f1c442f3957c6fedeb01a48d556 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/ptrace.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/stat.h> +#include <sys/user.h> +#include <sys/wait.h> +#include <sys/uio.h> +#include <linux/elf.h> +#include <linux/unistd.h> +#include <asm/ptrace.h>
+#include "../../kselftest_harness.h"
+#define ORIG_A0_MODIFY 0x01 +#define A0_MODIFY 0x02 +#define A0_OLD 0x03 +#define A0_NEW 0x04
Shouldn't A0_OLD and A0_NEW set more bits, since 3 and 4 aren't very unique (we could have those values by accident)? And should we include setting bits over 31 for 64-bit targets?
+#define perr_and_exit(fmt, ...) \
- ({ \
char buf[256]; \snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \__func__, __LINE__, ##__VA_ARGS__); \perror(buf); \exit(-1); \- })
Can we use e.g. ksft_exit_fail_perror() instead? I'd prefer we try to consolidate testing/selftests/riscv/* tests on a common format for errors and exit codes and we're already using other kselftest stuff.
+static inline void resume_and_wait_tracee(pid_t pid, int flag) +{
- int status;
- if (ptrace(flag, pid, 0, 0))
perr_and_exit("failed to resume the tracee %d\n", pid);- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);+}
+static void ptrace_test(int opt, int *result) +{
- int status;
- pid_t pid;
- struct user_regs_struct regs;
- struct iovec iov = {
.iov_base = ®s,.iov_len = sizeof(regs),- };
- unsigned long orig_a0;
- struct iovec a0_iov = {
.iov_base = &orig_a0,.iov_len = sizeof(orig_a0),- };
- pid = fork();
- if (pid == 0) {
/* Mark oneself being traced */long val = ptrace(PTRACE_TRACEME, 0, 0, 0);if (val)perr_and_exit("failed to request for tracer to trace me: %ld\n", val);kill(getpid(), SIGSTOP);/* Perform exit syscall that will be intercepted */exit(A0_OLD);- }
- if (pid < 0)
exit(1);This unexpected error condition deserves a message, so I'd use ksft_exit_fail_perror() here.
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);- /* Stop at the entry point of the syscall */
- resume_and_wait_tracee(pid, PTRACE_SYSCALL);
- /* Check tracee regs before the syscall */
- if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov))
perr_and_exit("failed to get tracee registers\n");- if (ptrace(PTRACE_GETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to get tracee registers\n");- if (orig_a0 != A0_OLD)
perr_and_exit("unexpected orig_a0: 0x%lx\n", orig_a0);- /* Modify a0/orig_a0 for the syscall */
- switch (opt) {
- case A0_MODIFY:
regs.a0 = A0_NEW;break;- case ORIG_A0_MODIFY:
orig_a0 = A0_NEW;break;- }
- if (ptrace(PTRACE_SETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to set tracee registers\n");- /* Resume the tracee */
- ptrace(PTRACE_CONT, pid, 0, 0);
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee\n");- *result = WEXITSTATUS(status);
+}
+TEST(ptrace_modify_a0) +{
- int result;
- ptrace_test(A0_MODIFY, &result);
- /* The modification of a0 cannot affect the first argument of the syscall */
- EXPECT_EQ(A0_OLD, result);
What about checking that we actually set regs.a0 to A0_NEW? We'd need A0_NEW to be more unique than 4, though.
+}
+TEST(ptrace_modify_orig_a0) +{
- int result;
- ptrace_test(ORIG_A0_MODIFY, &result);
- /* Only modify orig_a0 to change the first argument of the syscall */
If we run ptrace_modify_a0 first then we've already set regs.a0 to A0_NEW and can't check with this test that we don't set it to A0_NEW. We should probably have two different test values, one for regs.a0 and one for orig_a0 and ensure on both tests that we aren't writing both.
Celeste, do you want to fix this up or are you waiting for me to?
- Charlie
- EXPECT_EQ(A0_NEW, result);
+}
+TEST_HARNESS_MAIN
-- 2.47.0
Thanks, drew
On 2024-12-20 02:26, Charlie Jenkins wrote:
On Tue, Dec 03, 2024 at 01:55:07PM +0100, Andrew Jones wrote:
On Tue, Dec 03, 2024 at 05:30:05PM +0800, Celeste Liu wrote:
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com
tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 3 files changed, 139 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/riscv/abi/.gitignore b/tools/testing/selftests/riscv/abi/.gitignore index b38358f91c4d2240ae64892871d9ca98bda1ae58..378c605919a3b3d58eec2701eb7af430cfe315d6 100644 --- a/tools/testing/selftests/riscv/abi/.gitignore +++ b/tools/testing/selftests/riscv/abi/.gitignore @@ -1 +1,2 @@ pointer_masking +ptrace diff --git a/tools/testing/selftests/riscv/abi/Makefile b/tools/testing/selftests/riscv/abi/Makefile index ed82ff9c664e7eb3f760cbab81fb957ff72579c5..3f74d059dfdcbce4d45d8ff618781ccea1419061 100644 --- a/tools/testing/selftests/riscv/abi/Makefile +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -2,9 +2,12 @@ CFLAGS += -I$(top_srcdir)/tools/include -TEST_GEN_PROGS := pointer_masking +TEST_GEN_PROGS := pointer_masking ptrace include ../../lib.mk $(OUTPUT)/pointer_masking: pointer_masking.c $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
+$(OUTPUT)/ptrace: ptrace.c
- $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
diff --git a/tools/testing/selftests/riscv/abi/ptrace.c b/tools/testing/selftests/riscv/abi/ptrace.c new file mode 100644 index 0000000000000000000000000000000000000000..d192764b428d1f1c442f3957c6fedeb01a48d556 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/ptrace.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/stat.h> +#include <sys/user.h> +#include <sys/wait.h> +#include <sys/uio.h> +#include <linux/elf.h> +#include <linux/unistd.h> +#include <asm/ptrace.h>
+#include "../../kselftest_harness.h"
+#define ORIG_A0_MODIFY 0x01 +#define A0_MODIFY 0x02 +#define A0_OLD 0x03 +#define A0_NEW 0x04
Shouldn't A0_OLD and A0_NEW set more bits, since 3 and 4 aren't very unique (we could have those values by accident)? And should we include setting bits over 31 for 64-bit targets?
+#define perr_and_exit(fmt, ...) \
- ({ \
char buf[256]; \snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \__func__, __LINE__, ##__VA_ARGS__); \perror(buf); \exit(-1); \- })
Can we use e.g. ksft_exit_fail_perror() instead? I'd prefer we try to consolidate testing/selftests/riscv/* tests on a common format for errors and exit codes and we're already using other kselftest stuff.
+static inline void resume_and_wait_tracee(pid_t pid, int flag) +{
- int status;
- if (ptrace(flag, pid, 0, 0))
perr_and_exit("failed to resume the tracee %d\n", pid);- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);+}
+static void ptrace_test(int opt, int *result) +{
- int status;
- pid_t pid;
- struct user_regs_struct regs;
- struct iovec iov = {
.iov_base = ®s,.iov_len = sizeof(regs),- };
- unsigned long orig_a0;
- struct iovec a0_iov = {
.iov_base = &orig_a0,.iov_len = sizeof(orig_a0),- };
- pid = fork();
- if (pid == 0) {
/* Mark oneself being traced */long val = ptrace(PTRACE_TRACEME, 0, 0, 0);if (val)perr_and_exit("failed to request for tracer to trace me: %ld\n", val);kill(getpid(), SIGSTOP);/* Perform exit syscall that will be intercepted */exit(A0_OLD);- }
- if (pid < 0)
exit(1);This unexpected error condition deserves a message, so I'd use ksft_exit_fail_perror() here.
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);- /* Stop at the entry point of the syscall */
- resume_and_wait_tracee(pid, PTRACE_SYSCALL);
- /* Check tracee regs before the syscall */
- if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov))
perr_and_exit("failed to get tracee registers\n");- if (ptrace(PTRACE_GETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to get tracee registers\n");- if (orig_a0 != A0_OLD)
perr_and_exit("unexpected orig_a0: 0x%lx\n", orig_a0);- /* Modify a0/orig_a0 for the syscall */
- switch (opt) {
- case A0_MODIFY:
regs.a0 = A0_NEW;break;- case ORIG_A0_MODIFY:
orig_a0 = A0_NEW;break;- }
- if (ptrace(PTRACE_SETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to set tracee registers\n");- /* Resume the tracee */
- ptrace(PTRACE_CONT, pid, 0, 0);
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee\n");- *result = WEXITSTATUS(status);
+}
+TEST(ptrace_modify_a0) +{
- int result;
- ptrace_test(A0_MODIFY, &result);
- /* The modification of a0 cannot affect the first argument of the syscall */
- EXPECT_EQ(A0_OLD, result);
What about checking that we actually set regs.a0 to A0_NEW? We'd need A0_NEW to be more unique than 4, though.
+}
+TEST(ptrace_modify_orig_a0) +{
- int result;
- ptrace_test(ORIG_A0_MODIFY, &result);
- /* Only modify orig_a0 to change the first argument of the syscall */
If we run ptrace_modify_a0 first then we've already set regs.a0 to A0_NEW and can't check with this test that we don't set it to A0_NEW. We should probably have two different test values, one for regs.a0 and one for orig_a0 and ensure on both tests that we aren't writing both.
Celeste, do you want to fix this up or are you waiting for me to?
Sorry for delay. I was busy with household affairs in the past few weeks. v3 will be sent tomorrow or the day after tomorrow.
I am deeply sorry for this.
- Charlie
- EXPECT_EQ(A0_NEW, result);
+}
+TEST_HARNESS_MAIN
-- 2.47.0
Thanks, drew
On Fri, Dec 20, 2024 at 05:29:45AM +0800, Celeste Liu wrote:
On 2024-12-20 02:26, Charlie Jenkins wrote:
On Tue, Dec 03, 2024 at 01:55:07PM +0100, Andrew Jones wrote:
On Tue, Dec 03, 2024 at 05:30:05PM +0800, Celeste Liu wrote:
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com
tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 3 files changed, 139 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/riscv/abi/.gitignore b/tools/testing/selftests/riscv/abi/.gitignore index b38358f91c4d2240ae64892871d9ca98bda1ae58..378c605919a3b3d58eec2701eb7af430cfe315d6 100644 --- a/tools/testing/selftests/riscv/abi/.gitignore +++ b/tools/testing/selftests/riscv/abi/.gitignore @@ -1 +1,2 @@ pointer_masking +ptrace diff --git a/tools/testing/selftests/riscv/abi/Makefile b/tools/testing/selftests/riscv/abi/Makefile index ed82ff9c664e7eb3f760cbab81fb957ff72579c5..3f74d059dfdcbce4d45d8ff618781ccea1419061 100644 --- a/tools/testing/selftests/riscv/abi/Makefile +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -2,9 +2,12 @@ CFLAGS += -I$(top_srcdir)/tools/include -TEST_GEN_PROGS := pointer_masking +TEST_GEN_PROGS := pointer_masking ptrace include ../../lib.mk $(OUTPUT)/pointer_masking: pointer_masking.c $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
+$(OUTPUT)/ptrace: ptrace.c
- $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
diff --git a/tools/testing/selftests/riscv/abi/ptrace.c b/tools/testing/selftests/riscv/abi/ptrace.c new file mode 100644 index 0000000000000000000000000000000000000000..d192764b428d1f1c442f3957c6fedeb01a48d556 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/ptrace.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/stat.h> +#include <sys/user.h> +#include <sys/wait.h> +#include <sys/uio.h> +#include <linux/elf.h> +#include <linux/unistd.h> +#include <asm/ptrace.h>
+#include "../../kselftest_harness.h"
+#define ORIG_A0_MODIFY 0x01 +#define A0_MODIFY 0x02 +#define A0_OLD 0x03 +#define A0_NEW 0x04
Shouldn't A0_OLD and A0_NEW set more bits, since 3 and 4 aren't very unique (we could have those values by accident)? And should we include setting bits over 31 for 64-bit targets?
+#define perr_and_exit(fmt, ...) \
- ({ \
char buf[256]; \snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \__func__, __LINE__, ##__VA_ARGS__); \perror(buf); \exit(-1); \- })
Can we use e.g. ksft_exit_fail_perror() instead? I'd prefer we try to consolidate testing/selftests/riscv/* tests on a common format for errors and exit codes and we're already using other kselftest stuff.
+static inline void resume_and_wait_tracee(pid_t pid, int flag) +{
- int status;
- if (ptrace(flag, pid, 0, 0))
perr_and_exit("failed to resume the tracee %d\n", pid);- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);+}
+static void ptrace_test(int opt, int *result) +{
- int status;
- pid_t pid;
- struct user_regs_struct regs;
- struct iovec iov = {
.iov_base = ®s,.iov_len = sizeof(regs),- };
- unsigned long orig_a0;
- struct iovec a0_iov = {
.iov_base = &orig_a0,.iov_len = sizeof(orig_a0),- };
- pid = fork();
- if (pid == 0) {
/* Mark oneself being traced */long val = ptrace(PTRACE_TRACEME, 0, 0, 0);if (val)perr_and_exit("failed to request for tracer to trace me: %ld\n", val);kill(getpid(), SIGSTOP);/* Perform exit syscall that will be intercepted */exit(A0_OLD);- }
- if (pid < 0)
exit(1);This unexpected error condition deserves a message, so I'd use ksft_exit_fail_perror() here.
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);- /* Stop at the entry point of the syscall */
- resume_and_wait_tracee(pid, PTRACE_SYSCALL);
- /* Check tracee regs before the syscall */
- if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov))
perr_and_exit("failed to get tracee registers\n");- if (ptrace(PTRACE_GETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to get tracee registers\n");- if (orig_a0 != A0_OLD)
perr_and_exit("unexpected orig_a0: 0x%lx\n", orig_a0);- /* Modify a0/orig_a0 for the syscall */
- switch (opt) {
- case A0_MODIFY:
regs.a0 = A0_NEW;break;- case ORIG_A0_MODIFY:
orig_a0 = A0_NEW;break;- }
- if (ptrace(PTRACE_SETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to set tracee registers\n");- /* Resume the tracee */
- ptrace(PTRACE_CONT, pid, 0, 0);
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee\n");- *result = WEXITSTATUS(status);
+}
+TEST(ptrace_modify_a0) +{
- int result;
- ptrace_test(A0_MODIFY, &result);
- /* The modification of a0 cannot affect the first argument of the syscall */
- EXPECT_EQ(A0_OLD, result);
What about checking that we actually set regs.a0 to A0_NEW? We'd need A0_NEW to be more unique than 4, though.
+}
+TEST(ptrace_modify_orig_a0) +{
- int result;
- ptrace_test(ORIG_A0_MODIFY, &result);
- /* Only modify orig_a0 to change the first argument of the syscall */
If we run ptrace_modify_a0 first then we've already set regs.a0 to A0_NEW and can't check with this test that we don't set it to A0_NEW. We should probably have two different test values, one for regs.a0 and one for orig_a0 and ensure on both tests that we aren't writing both.
Celeste, do you want to fix this up or are you waiting for me to?
Sorry for delay. I was busy with household affairs in the past few weeks. v3 will be sent tomorrow or the day after tomorrow.
I am deeply sorry for this.
No need to apologize! Just wanted to make sure you weren't expected me to update the test :)
- Charlie
- Charlie
- EXPECT_EQ(A0_NEW, result);
+}
+TEST_HARNESS_MAIN
-- 2.47.0
Thanks, drew
linux-kselftest-mirror@lists.linaro.org
-
Alexandre Ghiti -
Andrew Jones -
Björn Töpel -
Celeste Liu -
Charlie Jenkins