From: Shaurya Rane Date: Tue, 18 Nov 2025 15:02:57 +0000 (+0530) Subject: cifs: fix memory leak in smb3_fs_context_parse_param error path X-Git-Tag: v6.18-rc7~12^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7e4d9120cfa413dd34f4f434befc5dbe6c38b2e5;p=thirdparty%2Fkernel%2Fstable.git cifs: fix memory leak in smb3_fs_context_parse_param error path 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 Signed-off-by: Shaurya Rane Signed-off-by: Steve French --- diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index 0f894d09157b..2a0d8b87bd8e 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1834,6 +1834,10 @@ 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; }