From e8c73eb7db0a498cd4b22d2819e6ab1a6f506bd6 Mon Sep 17 00:00:00 2001 From: Edward Adam Davis Date: Fri, 7 Nov 2025 22:01:39 +0800 Subject: [PATCH] cifs: client: fix memory leak in smb3_fs_context_parse_param The user calls fsconfig twice, but when the program exits, free() only frees ctx->source for the second fsconfig, not the first. Regarding fc->source, there is no code in the fs context related to its memory reclamation. To fix this memory leak, release the source memory corresponding to ctx or fc before each parsing. syzbot reported: BUG: memory leak unreferenced object 0xffff888128afa360 (size 96): backtrace (crc 79c9c7ba): kstrdup+0x3c/0x80 mm/util.c:84 smb3_fs_context_parse_param+0x229b/0x36c0 fs/smb/client/fs_context.c:1444 BUG: memory leak unreferenced object 0xffff888112c7d900 (size 96): backtrace (crc 79c9c7ba): smb3_fs_context_fullpath+0x70/0x1b0 fs/smb/client/fs_context.c:629 smb3_fs_context_parse_param+0x2266/0x36c0 fs/smb/client/fs_context.c:1438 Reported-by: syzbot+72afd4c236e6bc3f4bac@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=72afd4c236e6bc3f4bac Cc: stable@vger.kernel.org Reviewed-by: Paulo Alcantara (Red Hat) Signed-off-by: Edward Adam Davis Signed-off-by: Steve French --- fs/smb/client/fs_context.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index e60927b2a7c83..c2d5bb23040cf 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1435,12 +1435,14 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, cifs_errorf(fc, "Unknown error parsing devname\n"); goto cifs_parse_mount_err; } + kfree(ctx->source); ctx->source = smb3_fs_context_fullpath(ctx, '/'); if (IS_ERR(ctx->source)) { ctx->source = NULL; cifs_errorf(fc, "OOM when copying UNC string\n"); goto cifs_parse_mount_err; } + kfree(fc->source); fc->source = kstrdup(ctx->source, GFP_KERNEL); if (fc->source == NULL) { cifs_errorf(fc, "OOM when copying UNC string\n"); -- 2.47.3