6.1-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Borkmann daniel@iogearbox.net
[ Upstream commit 18752d73c1898fd001569195ba4b0b8c43255f4a ]
When checking malformed helper function signatures, also take other argument types into account aside from just ARG_PTR_TO_UNINIT_MEM.
This concerns (formerly) ARG_PTR_TO_{INT,LONG} given uninitialized memory can be passed there, too.
The func proto sanity check goes back to commit 435faee1aae9 ("bpf, verifier: add ARG_PTR_TO_RAW_STACK type"), and its purpose was to detect wrong func protos which had more than just one MEM_UNINIT-tagged type as arguments.
The reason more than one is currently not supported is as we mark stack slots with STACK_MISC in check_helper_call() in case of raw mode based on meta.access_size to allow uninitialized stack memory to be passed to helpers when they just write into the buffer.
Probing for base type as well as MEM_UNINIT tagging ensures that other types do not get missed (as it used to be the case for ARG_PTR_TO_{INT,LONG}).
Fixes: 57c3bb725a3d ("bpf: Introduce ARG_PTR_TO_{INT,LONG} arg types") Reported-by: Shung-Hsi Yu shung-hsi.yu@suse.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Andrii Nakryiko andrii@kernel.org Acked-by: Shung-Hsi Yu shung-hsi.yu@suse.com Link: https://lore.kernel.org/r/20240913191754.13290-4-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/verifier.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4efa50eb07d72..eb4073781a3c7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5796,6 +5796,12 @@ static bool arg_type_is_mem_size(enum bpf_arg_type type) type == ARG_CONST_SIZE_OR_ZERO; }
+static bool arg_type_is_raw_mem(enum bpf_arg_type type) +{ + return base_type(type) == ARG_PTR_TO_MEM && + type & MEM_UNINIT; +} + static bool arg_type_is_release(enum bpf_arg_type type) { return type & OBJ_RELEASE; @@ -6708,15 +6714,15 @@ static bool check_raw_mode_ok(const struct bpf_func_proto *fn) { int count = 0;
- if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg1_type)) count++; - if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg2_type)) count++; - if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg3_type)) count++; - if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg4_type)) count++; - if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg5_type)) count++;
/* We only support one arg being in raw mode at the moment,