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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-08-13 16:10:32 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-08-13 16:10:32 -0700 |
| commit | 6b0f8db921abf0520081d779876d3a41069dab95 (patch) | |
| tree | 85f8d7bdb4bb91fc41ff140e12786dc65c8d77e9 /fs | |
| parent | 6b4aa469f04999c3f244515fa7491b4d093c5167 (diff) | |
| parent | f50733b45d865f91db90919f8311e2127ce5a0cb (diff) | |
| download | lwn-6b0f8db921abf0520081d779876d3a41069dab95.tar.gz lwn-6b0f8db921abf0520081d779876d3a41069dab95.zip | |
Merge tag 'execve-v6.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve fixes from Kees Cook:
- binfmt_flat: Fix corruption when not offsetting data start
- exec: Fix ToCToU between perm check and set-uid/gid usage
* tag 'execve-v6.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
exec: Fix ToCToU between perm check and set-uid/gid usage
binfmt_flat: Fix corruption when not offsetting data start
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/binfmt_flat.c | 4 | ||||
| -rw-r--r-- | fs/exec.c | 8 |
2 files changed, 10 insertions, 2 deletions
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c index c26545d71d39..cd6d5bbb4b9d 100644 --- a/fs/binfmt_flat.c +++ b/fs/binfmt_flat.c @@ -72,8 +72,10 @@ #ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET #define DATA_START_OFFSET_WORDS (0) +#define MAX_SHARED_LIBS_UPDATE (0) #else #define DATA_START_OFFSET_WORDS (MAX_SHARED_LIBS) +#define MAX_SHARED_LIBS_UPDATE (MAX_SHARED_LIBS) #endif struct lib_info { @@ -880,7 +882,7 @@ static int load_flat_binary(struct linux_binprm *bprm) return res; /* Update data segment pointers for all libraries */ - for (i = 0; i < MAX_SHARED_LIBS; i++) { + for (i = 0; i < MAX_SHARED_LIBS_UPDATE; i++) { if (!libinfo.lib_list[i].loaded) continue; for (j = 0; j < MAX_SHARED_LIBS; j++) { diff --git a/fs/exec.c b/fs/exec.c index a126e3d1cacb..50e76cc633c4 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1692,6 +1692,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) unsigned int mode; vfsuid_t vfsuid; vfsgid_t vfsgid; + int err; if (!mnt_may_suid(file->f_path.mnt)) return; @@ -1708,12 +1709,17 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) /* Be careful if suid/sgid is set */ inode_lock(inode); - /* reload atomically mode/uid/gid now that lock held */ + /* Atomically reload and check mode/uid/gid now that lock held. */ mode = inode->i_mode; vfsuid = i_uid_into_vfsuid(idmap, inode); vfsgid = i_gid_into_vfsgid(idmap, inode); + err = inode_permission(idmap, inode, MAY_EXEC); inode_unlock(inode); + /* Did the exec bit vanish out from under us? Give up. */ + if (err) + return; + /* We ignore suid/sgid if there are no mappings for them in the ns */ if (!vfsuid_has_mapping(bprm->cred->user_ns, vfsuid) || !vfsgid_has_mapping(bprm->cred->user_ns, vfsgid)) |