[PATCH 5.17 0095/1126] cifs: fix NULL ptr dereference in smb2_ioctl_query_info()

Greg Kroah-Hartman
2022-04-05T07:52:26Z

From: Paulo Alcantara <pc@cjr.nz>

commit d6f5e358452479fa8a773b5c6ccc9e4ec5a20880 upstream.

When calling smb2_ioctl_query_info() with invalid
smb_query_info::flags, a NULL ptr dereference is triggered when trying
to kfree() uninitialised rqst[n].rq_iov array.

This also fixes leaked paths that are created in SMB2_open_init()
which required SMB2_open_free() to properly free them.

Here is a small C reproducer that triggers it

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>

#define die(s) perror(s), exit(1)
#define QUERY_INFO 0xc018cf07

int main(int argc, char *argv[])
{
int fd;

if (argc < 2)
exit(1);
fd = open(argv[1], O_RDONLY);
if (fd == -1)
die("open");
if (ioctl(fd, QUERY_INFO, (uint32_t[]) { 0, 0, 0, 4, 0, 0}) == -1)
die("ioctl");
close(fd);
return 0;
}

mount.cifs //srv/share /mnt -o ...
gcc repro.c && ./a.out /mnt/f0

[ 1832.124468] CIFS: VFS: \\w22-dc.zelda.test\test Invalid passthru query flags: 0x4
[ 1832.125043] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ 1832.125764] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[ 1832.126241] CPU: 3 PID: 1133 Comm: a.out Not tainted 5.17.0-rc8 #2
[ 1832.126630] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014
[ 1832.127322] RIP: 0010:smb2_ioctl_query_info+0x7a3/0xe30 [cifs]
[ 1832.127749] Code: 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 6c 05 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 74 24 28 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 cb 04 00 00 49 8b 3e e8 bb fc fa ff 48 89 da 48
[ 1832.128911] RSP: 0018:ffffc90000957b08 EFLAGS: 00010256
[ 1832.129243] RAX: dffffc0000000000 RBX: ffff888117e9b850 RCX: ffffffffa020580d
[ 1832.129691] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffffa043a2c0
[ 1832.130137] RBP: ffff888117e9b878 R08: 0000000000000001 R09: 0000000000000003
[ 1832.130585] R10: fffffbfff4087458 R11: 0000000000000001 R12: ffff888117e9b800
[ 1832.131037] R13: 00000000ffffffea R14: 0000000000000000 R15: ffff888117e9b8a8
[ 1832.131485] FS: 00007fcee9900740(0000) GS:ffff888151a00000(0000) knlGS:0000000000000000
[ 1832.131993] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1832.132354] CR2: 00007fcee9a1ef5e CR3: 0000000114cd2000 CR4: 0000000000350ee0
[ 1832.132801] Call Trace:
[ 1832.132962] <TASK>
[ 1832.133104] ? smb2_query_reparse_tag+0x890/0x890 [cifs]
[ 1832.133489] ? cifs_mapchar+0x460/0x460 [cifs]
[ 1832.133822] ? rcu_read_lock_sched_held+0x3f/0x70
[ 1832.134125] ? cifs_strndup_to_utf16+0x15b/0x250 [cifs]
[ 1832.134502] ? lock_downgrade+0x6f0/0x6f0
[ 1832.134760] ? cifs_convert_path_to_utf16+0x198/0x220 [cifs]
[ 1832.135170] ? smb2_check_message+0x1080/0x1080 [cifs]
[ 1832.135545] cifs_ioctl+0x1577/0x3320 [cifs]
[ 1832.135864] ? lock_downgrade+0x6f0/0x6f0
[ 1832.136125] ? cifs_readdir+0x2e60/0x2e60 [cifs]
[ 1832.136468] ? rcu_read_lock_sched_held+0x3f/0x70
[ 1832.136769] ? __rseq_handle_notify_resume+0x80b/0xbe0
[ 1832.137096] ? __up_read+0x192/0x710
[ 1832.137327] ? __ia32_sys_rseq+0xf0/0xf0
[ 1832.137578] ? __x64_sys_openat+0x11f/0x1d0
[ 1832.137850] __x64_sys_ioctl+0x127/0x190
[ 1832.138103] do_syscall_64+0x3b/0x90
[ 1832.138378] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 1832.138702] RIP: 0033:0x7fcee9a253df
[ 1832.138937] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 77 1f 48 8b 44 24 18 64 48 2b 04 25 28 00
[ 1832.140107] RSP: 002b:00007ffeba94a8a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 1832.140606] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcee9a253df
[ 1832.141058] RDX: 00007ffeba94a910 RSI: 00000000c018cf07 RDI: 0000000000000003
[ 1832.141503] RBP: 00007ffeba94a930 R08: 00007fcee9b24db0 R09: 00007fcee9b45c4e
[ 1832.141948] R10: 00007fcee9918d40 R11: 0000000000000246 R12: 00007ffeba94aa48
[ 1832.142396] R13: 0000000000401176 R14: 0000000000403df8 R15: 00007fcee9b78000
[ 1832.142851] </TASK>
[ 1832.142994] Modules linked in: cifs cifs_arc4 cifs_md4 bpf_preload [last unloaded: cifs]

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/cifs/smb2ops.c | 124 ++++++++++++++++++++++++++++--------------------------
1 file changed, 65 insertions(+), 59 deletions(-)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1643,6 +1643,7 @@ smb2_ioctl_query_info(const unsigned int
unsigned int size[2];
void *data[2];
int create_options = is_dir ? CREATE_NOT_FILE : CREATE_NOT_DIR;
+ void (*free_req1_func)(struct smb_rqst *r);

vars = kzalloc(sizeof(*vars), GFP_ATOMIC);
if (vars == NULL)
@@ -1652,17 +1653,18 @@ smb2_ioctl_query_info(const unsigned int

resp_buftype[0] = resp_buftype[1] = resp_buftype[2] = CIFS_NO_BUFFER;

- if (copy_from_user(&qi, arg, sizeof(struct smb_query_info)))
- goto e_fault;
-
+ if (copy_from_user(&qi, arg, sizeof(struct smb_query_info))) {
+ rc = -EFAULT;
+ goto free_vars;
+ }
if (qi.output_buffer_length > 1024) {
- kfree(vars);
- return -EINVAL;
+ rc = -EINVAL;
+ goto free_vars;
}

if (!ses || !server) {
- kfree(vars);
- return -EIO;
+ rc = -EIO;
+ goto free_vars;
}

if (smb3_encryption_required(tcon))
@@ -1671,8 +1673,8 @@ smb2_ioctl_query_info(const unsigned int
if (qi.output_buffer_length) {
buffer = memdup_user(arg + sizeof(struct smb_query_info), qi.output_buffer_length);
if (IS_ERR(buffer)) {
- kfree(vars);
- return PTR_ERR(buffer);
+ rc = PTR_ERR(buffer);
+ goto free_vars;
}
}

@@ -1711,48 +1713,45 @@ smb2_ioctl_query_info(const unsigned int
rc = SMB2_open_init(tcon, server,
&rqst[0], &oplock, &oparms, path);
if (rc)
- goto iqinf_exit;
+ goto free_output_buffer;
smb2_set_next_command(tcon, &rqst[0]);

/* Query */
if (qi.flags & PASSTHRU_FSCTL) {
/* Can eventually relax perm check since server enforces too */
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable(CAP_SYS_ADMIN)) {
rc = -EPERM;
- else {
- rqst[1].rq_iov = &vars->io_iov[0];
- rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
-
- rc = SMB2_ioctl_init(tcon, server,
- &rqst[1],
- COMPOUND_FID, COMPOUND_FID,
- qi.info_type, true, buffer,
- qi.output_buffer_length,
- CIFSMaxBufSize -
- MAX_SMB2_CREATE_RESPONSE_SIZE -
- MAX_SMB2_CLOSE_RESPONSE_SIZE);
+ goto free_open_req;
}
+ rqst[1].rq_iov = &vars->io_iov[0];
+ rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
+
+ rc = SMB2_ioctl_init(tcon, server, &rqst[1], COMPOUND_FID, COMPOUND_FID,
+ qi.info_type, true, buffer, qi.output_buffer_length,
+ CIFSMaxBufSize - MAX_SMB2_CREATE_RESPONSE_SIZE -
+ MAX_SMB2_CLOSE_RESPONSE_SIZE);
+ free_req1_func = SMB2_ioctl_free;
} else if (qi.flags == PASSTHRU_SET_INFO) {
/* Can eventually relax perm check since server enforces too */
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable(CAP_SYS_ADMIN)) {
rc = -EPERM;
- else if (qi.output_buffer_length < 8)
+ goto free_open_req;
+ }
+ if (qi.output_buffer_length < 8) {
rc = -EINVAL;
- else {
- rqst[1].rq_iov = &vars->si_iov[0];
- rqst[1].rq_nvec = 1;
-
- /* MS-FSCC 2.4.13 FileEndOfFileInformation */
- size[0] = 8;
- data[0] = buffer;
-
- rc = SMB2_set_info_init(tcon, server,
- &rqst[1],
- COMPOUND_FID, COMPOUND_FID,
- current->tgid,
- FILE_END_OF_FILE_INFORMATION,
- SMB2_O_INFO_FILE, 0, data, size);
+ goto free_open_req;
}
+ rqst[1].rq_iov = &vars->si_iov[0];
+ rqst[1].rq_nvec = 1;
+
+ /* MS-FSCC 2.4.13 FileEndOfFileInformation */
+ size[0] = 8;
+ data[0] = buffer;
+
+ rc = SMB2_set_info_init(tcon, server, &rqst[1], COMPOUND_FID, COMPOUND_FID,
+ current->tgid, FILE_END_OF_FILE_INFORMATION,
+ SMB2_O_INFO_FILE, 0, data, size);
+ free_req1_func = SMB2_set_info_free;
} else if (qi.flags == PASSTHRU_QUERY_INFO) {
rqst[1].rq_iov = &vars->qi_iov[0];
rqst[1].rq_nvec = 1;
@@ -1763,6 +1762,7 @@ smb2_ioctl_query_info(const unsigned int
qi.info_type, qi.additional_information,
qi.input_buffer_length,
qi.output_buffer_length, buffer);
+ free_req1_func = SMB2_query_info_free;
} else { /* unknown flags */
cifs_tcon_dbg(VFS, "Invalid passthru query flags: 0x%x\n",
qi.flags);
@@ -1770,7 +1770,7 @@ smb2_ioctl_query_info(const unsigned int
}

if (rc)
- goto iqinf_exit;
+ goto free_open_req;
smb2_set_next_command(tcon, &rqst[1]);
smb2_set_related(&rqst[1]);

@@ -1781,14 +1781,14 @@ smb2_ioctl_query_info(const unsigned int
rc = SMB2_close_init(tcon, server,
&rqst[2], COMPOUND_FID, COMPOUND_FID, false);
if (rc)
- goto iqinf_exit;
+ goto free_req_1;
smb2_set_related(&rqst[2]);

rc = compound_send_recv(xid, ses, server,
flags, 3, rqst,
resp_buftype, rsp_iov);
if (rc)
- goto iqinf_exit;
+ goto out;

/* No need to bump num_remote_opens since handle immediately closed */
if (qi.flags & PASSTHRU_FSCTL) {
@@ -1798,18 +1798,22 @@ smb2_ioctl_query_info(const unsigned int
qi.input_buffer_length = le32_to_cpu(io_rsp->OutputCount);
if (qi.input_buffer_length > 0 &&
le32_to_cpu(io_rsp->OutputOffset) + qi.input_buffer_length
- > rsp_iov[1].iov_len)
- goto e_fault;
+ > rsp_iov[1].iov_len) {
+ rc = -EFAULT;
+ goto out;
+ }

if (copy_to_user(&pqi->input_buffer_length,
&qi.input_buffer_length,
- sizeof(qi.input_buffer_length)))
- goto e_fault;
+ sizeof(qi.input_buffer_length))) {
+ rc = -EFAULT;
+ goto out;
+ }

if (copy_to_user((void __user *)pqi + sizeof(struct smb_query_info),
(const void *)io_rsp + le32_to_cpu(io_rsp->OutputOffset),
qi.input_buffer_length))
- goto e_fault;
+ rc = -EFAULT;
} else {
pqi = (struct smb_query_info __user *)arg;
qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
@@ -1817,28 +1821,30 @@ smb2_ioctl_query_info(const unsigned int
qi.input_buffer_length = le32_to_cpu(qi_rsp->OutputBufferLength);
if (copy_to_user(&pqi->input_buffer_length,
&qi.input_buffer_length,
- sizeof(qi.input_buffer_length)))
- goto e_fault;
+ sizeof(qi.input_buffer_length))) {
+ rc = -EFAULT;
+ goto out;
+ }

if (copy_to_user(pqi + 1, qi_rsp->Buffer,
qi.input_buffer_length))
- goto e_fault;
+ rc = -EFAULT;
}

- iqinf_exit:
- cifs_small_buf_release(rqst[0].rq_iov[0].iov_base);
- cifs_small_buf_release(rqst[1].rq_iov[0].iov_base);
- cifs_small_buf_release(rqst[2].rq_iov[0].iov_base);
+out:
free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
free_rsp_buf(resp_buftype[2], rsp_iov[2].iov_base);
- kfree(vars);
+ SMB2_close_free(&rqst[2]);
+free_req_1:
+ free_req1_func(&rqst[1]);
+free_open_req:
+ SMB2_open_free(&rqst[0]);
+free_output_buffer:
kfree(buffer);
+free_vars:
+ kfree(vars);
return rc;
-
-e_fault:
- rc = -EFAULT;
- goto iqinf_exit;
}

static ssize_t