diff options
| author | Kees Cook <keescook@chromium.org> | 2022-12-09 22:54:57 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-12-31 15:33:07 +0300 |
| commit | 2c5e64f0a8d356616329ea26382b86dd191f9d70 (patch) | |
| tree | 73924a77a76515625c7ff620622c33a7a035450d /security/loadpin | |
| parent | 2d57269cabeb52c6e80223a9d838e0a758005af7 (diff) | |
| download | linux-2c5e64f0a8d356616329ea26382b86dd191f9d70.tar.xz | |
LoadPin: Ignore the "contents" argument of the LSM hooks
[ Upstream commit 1a17e5b513ceebf21100027745b8731b4728edf7 ]
LoadPin only enforces the read-only origin of kernel file reads. Whether
or not it was a partial read isn't important. Remove the overly
conservative checks so that things like partial firmware reads will
succeed (i.e. reading a firmware header).
Fixes: 2039bda1fa8d ("LSM: Add "contents" flag to kernel_read_file hook")
Cc: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Tested-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://lore.kernel.org/r/20221209195453.never.494-kees@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'security/loadpin')
| -rw-r--r-- | security/loadpin/loadpin.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c index de41621f4998..110a5ab2b46b 100644 --- a/security/loadpin/loadpin.c +++ b/security/loadpin/loadpin.c @@ -122,21 +122,11 @@ static void loadpin_sb_free_security(struct super_block *mnt_sb) } } -static int loadpin_read_file(struct file *file, enum kernel_read_file_id id, - bool contents) +static int loadpin_check(struct file *file, enum kernel_read_file_id id) { struct super_block *load_root; const char *origin = kernel_read_file_id_str(id); - /* - * If we will not know that we'll be seeing the full contents - * then we cannot trust a load will be complete and unchanged - * off disk. Treat all contents=false hooks as if there were - * no associated file struct. - */ - if (!contents) - file = NULL; - /* If the file id is excluded, ignore the pinning. */ if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) && ignore_read_file_id[id]) { @@ -192,9 +182,25 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id, return 0; } +static int loadpin_read_file(struct file *file, enum kernel_read_file_id id, + bool contents) +{ + /* + * LoadPin only cares about the _origin_ of a file, not its + * contents, so we can ignore the "are full contents available" + * argument here. + */ + return loadpin_check(file, id); +} + static int loadpin_load_data(enum kernel_load_data_id id, bool contents) { - return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents); + /* + * LoadPin only cares about the _origin_ of a file, not its + * contents, so a NULL file is passed, and we can ignore the + * state of "contents". + */ + return loadpin_check(NULL, (enum kernel_read_file_id) id); } static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = { |