From: Edward Adam Davis <eadavis@qq.com> stable inclusion from stable-v6.6.117 commit 868fc62811d3fabcf5685e14f36377a855d5412d category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/12582 CVE: CVE-2025-40268 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit e8c73eb7db0a498cd4b22d2819e6ab1a6f506bd6 upstream. 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) <pc@manguebit.org> Signed-off-by: Edward Adam Davis <eadavis@qq.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Wang Zhaolong <wangzhaolong@huaweicloud.com> --- 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 137d03781d52..cf233cb9c194 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1359,16 +1359,18 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, goto cifs_parse_mount_err; default: 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"); goto cifs_parse_mount_err; } -- 2.34.3