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authorDavid Disseldorp <ddiss@suse.de>2021-04-23 01:14:03 +0300
committerSteve French <stfrench@microsoft.com>2021-04-26 00:28:24 +0300
commit315db9a05b7a56810728589baa930864107e4634 (patch)
treec115e12a227a2b13a76d2bbbe7836cb45d74efa8 /fs
parentad7567bc65afe0ef0d1b853aa4d54c44d09223dc (diff)
downloadlinux-315db9a05b7a56810728589baa930864107e4634.tar.xz
cifs: fix leak in cifs_smb3_do_mount() ctx
cifs_smb3_do_mount() calls smb3_fs_context_dup() and then cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname() call overwrites the cifs_sb->ctx->UNC string already dup'ed by smb3_fs_context_dup(), resulting in a leak. E.g. unreferenced object 0xffff888002980420 (size 32): comm "mount", pid 160, jiffies 4294892541 (age 30.416s) hex dump (first 32 bytes): 5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10 34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share.. backtrace: [<00000000069e12f6>] kstrdup+0x28/0x50 [<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs] [<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs] [<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs] [<00000000716f731e>] vfs_get_tree+0x1b/0x90 [<00000000491d3892>] path_mount+0x62a/0x910 [<0000000046b2e774>] do_mount+0x50/0x70 [<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0 [<00000000b5122496>] do_syscall_64+0x33/0x40 [<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae This change is a bandaid until the cifs_setup_volume_info() TODO and error handling issues are resolved. Signed-off-by: David Disseldorp <ddiss@suse.de> Acked-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> CC: <stable@vger.kernel.org> # v5.11+ Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/cifsfs.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 4257f841ec4e..39f4889a036b 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -855,6 +855,12 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
goto out;
}
+ /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */
+ kfree(cifs_sb->ctx->UNC);
+ cifs_sb->ctx->UNC = NULL;
+ kfree(cifs_sb->ctx->prepath);
+ cifs_sb->ctx->prepath = NULL;
+
rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
if (rc) {
root = ERR_PTR(rc);