diff options
| author | Kees Cook | 2022-09-16 17:11:18 -0700 |
|---|---|---|
| committer | Kees Cook | 2024-01-22 11:45:39 -0800 |
| commit | bdd8f62431ebcf15902a5fce3336388e436405c6 (patch) | |
| tree | efbc4718f1dfcf8341d5f4b895fdd264d284fca3 /fs/exec.c | |
| parent | 8788a17c2319f020ccdc3f2907179a5ae81b7ad6 (diff) | |
exec: Add do_close_execat() helper
Consolidate the calls to allow_write_access()/fput() into a single
place, since we repeat this code pattern. Add comments around the
callers for the details on it.
Link: https://lore.kernel.org/r/202209161637.9EDAF6B18@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/fs/exec.c b/fs/exec.c index ba7d0548ac57..2037cc636036 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -904,6 +904,10 @@ EXPORT_SYMBOL(transfer_args_to_stack); #endif /* CONFIG_MMU */ +/* + * On success, caller must call do_close_execat() on the returned + * struct file to close it. + */ static struct file *do_open_execat(int fd, struct filename *name, int flags) { struct file *file; @@ -948,6 +952,17 @@ exit: return ERR_PTR(err); } +/** + * open_exec - Open a path name for execution + * + * @name: path name to open with the intent of executing it. + * + * Returns ERR_PTR on failure or allocated struct file on success. + * + * As this is a wrapper for the internal do_open_execat(), callers + * must call allow_write_access() before fput() on release. Also see + * do_close_execat(). + */ struct file *open_exec(const char *name) { struct filename *filename = getname_kernel(name); @@ -1484,6 +1499,15 @@ static int prepare_bprm_creds(struct linux_binprm *bprm) return -ENOMEM; } +/* Matches do_open_execat() */ +static void do_close_execat(struct file *file) +{ + if (!file) + return; + allow_write_access(file); + fput(file); +} + static void free_bprm(struct linux_binprm *bprm) { if (bprm->mm) { @@ -1495,10 +1519,7 @@ static void free_bprm(struct linux_binprm *bprm) mutex_unlock(¤t->signal->cred_guard_mutex); abort_creds(bprm->cred); } - if (bprm->file) { - allow_write_access(bprm->file); - fput(bprm->file); - } + do_close_execat(bprm->file); if (bprm->executable) fput(bprm->executable); /* If a binfmt changed the interp, free it. */ @@ -1520,8 +1541,7 @@ static struct linux_binprm *alloc_bprm(int fd, struct filename *filename, int fl bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); if (!bprm) { - allow_write_access(file); - fput(file); + do_close_execat(file); return ERR_PTR(-ENOMEM); } |