6.17-stable review patch. If anyone has any objections, please let me know.
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From: Shaurya Rane ssrane_b23@ee.vjti.ac.in
[ Upstream commit 7e4d9120cfa413dd34f4f434befc5dbe6c38b2e5 ]
Add proper cleanup of ctx->source and fc->source to the cifs_parse_mount_err error handler. This ensures that memory allocated for the source strings is correctly freed on all error paths, matching the cleanup already performed in the success path by smb3_cleanup_fs_context_contents(). Pointers are also set to NULL after freeing to prevent potential double-free issues.
This change fixes a memory leak originally detected by syzbot. The leak occurred when processing Opt_source mount options if an error happened after ctx->source and fc->source were successfully allocated but before the function completed.
The specific leak sequence was: 1. ctx->source = smb3_fs_context_fullpath(ctx, '/') allocates memory 2. fc->source = kstrdup(ctx->source, GFP_KERNEL) allocates more memory 3. A subsequent error jumps to cifs_parse_mount_err 4. The old error handler freed passwords but not the source strings, causing the memory to leak.
This issue was not addressed by commit e8c73eb7db0a ("cifs: client: fix memory leak in smb3_fs_context_parse_param"), which only fixed leaks from repeated fsconfig() calls but not this error path.
Patch updated with minor change suggested by kernel test robot
Reported-by: syzbot+87be6809ed9bf6d718e3@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=87be6809ed9bf6d718e3 Fixes: 24e0a1eff9e2 ("cifs: switch to new mount api") Reviewed-by: David Howells dhowells@redhat.com Signed-off-by: Shaurya Rane ssrane_b23@ee.vjti.ac.in Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/smb/client/fs_context.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index 55ea0ad894449..c9cd00b96cde1 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1829,6 +1829,10 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->password = NULL; kfree_sensitive(ctx->password2); ctx->password2 = NULL; + kfree(ctx->source); + ctx->source = NULL; + kfree(fc->source); + fc->source = NULL; return -EINVAL; }