From: Kees Cook keescook@chromium.org
commit c307459b9d1fcb8bbf3ea5a4162979532322ef77 upstream.
FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs that are interested in filtering between types of things. The "how" should be an internal detail made uninteresting to the LSMs.
Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") Signed-off-by: Kees Cook keescook@chromium.org Reviewed-by: Mimi Zohar zohar@linux.ibm.com Reviewed-by: Luis Chamberlain mcgrof@kernel.org Acked-by: Scott Branden scott.branden@broadcom.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/base/firmware_loader/main.c | 5 ++--- fs/exec.c | 7 ++++--- include/linux/fs.h | 1 - kernel/module.c | 2 +- security/integrity/digsig.c | 2 +- security/integrity/ima/ima_fs.c | 2 +- security/integrity/ima/ima_main.c | 6 ++---- 7 files changed, 11 insertions(+), 14 deletions(-)
--- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -470,14 +470,12 @@ fw_get_filesystem_firmware(struct device int i, len; int rc = -ENOENT; char *path; - enum kernel_read_file_id id = READING_FIRMWARE; size_t msize = INT_MAX; void *buffer = NULL;
/* Already populated data member means we're loading into a buffer */ if (!decompress && fw_priv->data) { buffer = fw_priv->data; - id = READING_FIRMWARE_PREALLOC_BUFFER; msize = fw_priv->allocated_size; }
@@ -501,7 +499,8 @@ fw_get_filesystem_firmware(struct device
/* load firmware files from the mount namespace of init */ rc = kernel_read_file_from_path_initns(path, &buffer, - &size, msize, id); + &size, msize, + READING_FIRMWARE); if (rc) { if (rc != -ENOENT) dev_warn(device, "loading %s failed with error %d\n", --- a/fs/exec.c +++ b/fs/exec.c @@ -955,6 +955,7 @@ int kernel_read_file(struct file *file, { loff_t i_size, pos; ssize_t bytes = 0; + void *allocated = NULL; int ret;
if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) @@ -978,8 +979,8 @@ int kernel_read_file(struct file *file, goto out; }
- if (id != READING_FIRMWARE_PREALLOC_BUFFER) - *buf = vmalloc(i_size); + if (!*buf) + *buf = allocated = vmalloc(i_size); if (!*buf) { ret = -ENOMEM; goto out; @@ -1008,7 +1009,7 @@ int kernel_read_file(struct file *file,
out_free: if (ret < 0) { - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { + if (allocated) { vfree(*buf); *buf = NULL; } --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2861,7 +2861,6 @@ extern int do_pipe_flags(int *, int); #define __kernel_read_file_id(id) \ id(UNKNOWN, unknown) \ id(FIRMWARE, firmware) \ - id(FIRMWARE_PREALLOC_BUFFER, firmware) \ id(MODULE, kernel-module) \ id(KEXEC_IMAGE, kexec-image) \ id(KEXEC_INITRAMFS, kexec-initramfs) \ --- a/kernel/module.c +++ b/kernel/module.c @@ -4028,7 +4028,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, c { struct load_info info = { }; loff_t size; - void *hdr; + void *hdr = NULL; int err;
err = may_init_module(); --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -169,7 +169,7 @@ int __init integrity_add_key(const unsig
int __init integrity_load_x509(const unsigned int id, const char *path) { - void *data; + void *data = NULL; loff_t size; int rc; key_perm_t perm; --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -272,7 +272,7 @@ static const struct file_operations ima_
static ssize_t ima_read_policy(char *path) { - void *data; + void *data = NULL; char *datap; loff_t size; int rc, pathlen = strlen(path); --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -621,19 +621,17 @@ void ima_post_path_mknod(struct dentry * int ima_read_file(struct file *file, enum kernel_read_file_id read_id) { /* - * READING_FIRMWARE_PREALLOC_BUFFER - * * Do devices using pre-allocated memory run the risk of the * firmware being accessible to the device prior to the completion * of IMA's signature verification any more than when using two - * buffers? + * buffers? It may be desirable to include the buffer address + * in this API and walk all the dma_map_single() mappings to check. */ return 0; }
const int read_idmap[READING_MAX_ID] = { [READING_FIRMWARE] = FIRMWARE_CHECK, - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK, [READING_MODULE] = MODULE_CHECK, [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,