mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-31 10:31:33 -04:00
Code Issues Packages Projects Releases Wiki Activity

binfmt_misc: return errors directly in load_misc_binary()

Browse Source 
load_misc_binary() seeds retval with the error for checks that
happen further down, reassigns it along the way and funnels every
exit through a ret label whose only job is dropping the entry
reference, so figuring out what an early return actually returns
means replaying the assignment history. Give put_binfmt_handler() a
cleanup class and take the reference with __free() so every failure
can return its error right where the condition is checked. The
comment at the label restated what the put_binfmt_handler()
kernel-doc already explains, it goes with the label. Drop the dead
NULL initialization of interp_file which is assigned on all paths
before use.

No functional change.

Link: https://patch.msgid.link/20260710-work-binfmt_misc-locking-v3-15-a162f7cb58d6@kernel.org
Reviewed-by: Jori Koolstra <jkoolstra@xs4all.nl>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Christian Brauner
2026-07-10 11:33:16 +02:00
parent 9c17e93afa
commit 0eec8a0428
1 changed files with 14 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
fs/binfmt_misc.c
View File

@@ -183,6 +183,8 @@ static void put_binfmt_handler(struct binfmt_misc_entry *e)
}
}
DEFINE_FREE(put_binfmt_handler, struct binfmt_misc_entry *, if (_T) put_binfmt_handler(_T))
/**
* current_binfmt_misc - get the binfmt_misc instance of the caller's user namespace
*
@@ -215,48 +217,47 @@ static struct binfmt_misc *current_binfmt_misc(void)
*/
static int load_misc_binary(struct linux_binprm *bprm)
{
struct binfmt_misc_entry *fmt;
struct file *interp_file = NULL;
int retval = -ENOEXEC;
struct binfmt_misc_entry *fmt __free(put_binfmt_handler) = NULL;
struct file *interp_file;
struct binfmt_misc *misc;
int retval;
misc = current_binfmt_misc();
if (!READ_ONCE(misc->enabled))
return retval;
return -ENOEXEC;
fmt = get_binfmt_handler(misc, bprm);
if (!fmt)
return retval;
return -ENOEXEC;
/* Need to be able to load the file after exec */
retval = -ENOENT;
if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
goto ret;
return -ENOENT;
if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) {
bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0;
} else {
retval = remove_arg_zero(bprm);
if (retval)
goto ret;
return retval;
}
/* make argv[1] be the path to the binary */
retval = copy_string_kernel(bprm->interp, bprm);
if (retval < 0)
goto ret;
return retval;
bprm->argc++;
/* add the interp as argv[0] */
retval = copy_string_kernel(fmt->interpreter, bprm);
if (retval < 0)
goto ret;
return retval;
bprm->argc++;
/* Update interp in case binfmt_script needs it. */
retval = bprm_change_interp(fmt->interpreter, bprm);
if (retval < 0)
goto ret;
return retval;
if (fmt->flags & MISC_FMT_OPEN_FILE) {
interp_file = file_clone_open(fmt->interp_file);
@@ -271,29 +272,15 @@ static int load_misc_binary(struct linux_binprm *bprm)
} else {
interp_file = open_exec(fmt->interpreter);
}
retval = PTR_ERR(interp_file);
if (IS_ERR(interp_file))
goto ret;
return PTR_ERR(interp_file);
bprm->interpreter = interp_file;
if (fmt->flags & MISC_FMT_OPEN_BINARY)
bprm->have_execfd = 1;
if (fmt->flags & MISC_FMT_CREDENTIALS)
bprm->execfd_creds = 1;
retval = 0;
ret:
/*
* If we actually put the entry here all concurrent calls to
* load_misc_binary() will have finished. We also know
* that for the refcount to be zero someone must have concurently
* removed the binary type handler from the list and it's our job to
* free it.
*/
put_binfmt_handler(fmt);
return retval;
return 0;
}
/* Command parsers */