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authorChristian Brauner <christian.brauner@ubuntu.com>2021-07-14 15:47:50 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-14 18:19:06 +0200
commitd1d488d813703618f0dd93f0e4c4a05928114aa8 (patch)
treeb1115033156bb1945244b3000489d84a4b5a68ee /kernel
parentcgroup: verify that source is a string (diff)
downloadlinux-d1d488d813703618f0dd93f0e4c4a05928114aa8.tar.xz
linux-d1d488d813703618f0dd93f0e4c4a05928114aa8.zip
fs: add vfs_parse_fs_param_source() helper
Add a simple helper that filesystems can use in their parameter parser to parse the "source" parameter. A few places open-coded this function and that already caused a bug in the cgroup v1 parser that we fixed. Let's make it harder to get this wrong by introducing a helper which performs all necessary checks. Link: https://syzkaller.appspot.com/bug?id=6312526aba5beae046fdae8f00399f87aab48b12 Cc: Christoph Hellwig <hch@lst.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup/cgroup-v1.c14
1 files changed, 5 insertions, 9 deletions
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 527917c0b30b..8d6bf56ed77a 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -911,15 +911,11 @@ int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
opt = fs_parse(fc, cgroup1_fs_parameters, param, &result);
if (opt == -ENOPARAM) {
- if (strcmp(param->key, "source") == 0) {
- if (param->type != fs_value_is_string)
- return invalf(fc, "Non-string source");
- if (fc->source)
- return invalf(fc, "Multiple sources not supported");
- fc->source = param->string;
- param->string = NULL;
- return 0;
- }
+ int ret;
+
+ ret = vfs_parse_fs_param_source(fc, param);
+ if (ret != -ENOPARAM)
+ return ret;
for_each_subsys(ss, i) {
if (strcmp(param->key, ss->legacy_name))
continue;