From: butt3rflyh4ck <redacted>
This check was incomplete, did not consider size is 0:
if (len != ALIGN(size, 4) + hdrlen)
goto err;
if size from qrtr_hdr is 0, the result of ALIGN(size, 4)
will be 0, In case of len == hdrlen and size == 0
in header this check won't fail and
if (cb->type == QRTR_TYPE_NEW_SERVER) {
/* Remote node endpoint can bridge other distant nodes */
const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
}
will also read out of bound from data, which is hdrlen allocated block.
Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Fixes: ad9d24c9429e ("net: qrtr: fix OOB Read in qrtr_endpoint_post")
Signed-off-by: butt3rflyh4ck <redacted>
---
net/qrtr/qrtr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
From: Jakub Kicinski <kuba@kernel.org> Date: 2021-08-19 19:16:34
On Fri, 20 Aug 2021 02:14:58 +0800 butt3rflyh4ck wrote:
From: butt3rflyh4ck <redacted>
This check was incomplete, did not consider size is 0:
if (len != ALIGN(size, 4) + hdrlen)
goto err;
if size from qrtr_hdr is 0, the result of ALIGN(size, 4)
will be 0, In case of len == hdrlen and size == 0
in header this check won't fail and
if (cb->type == QRTR_TYPE_NEW_SERVER) {
/* Remote node endpoint can bridge other distant nodes */
const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
}
will also read out of bound from data, which is hdrlen allocated block.
Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Fixes: ad9d24c9429e ("net: qrtr: fix OOB Read in qrtr_endpoint_post")
Please make sure to CC authors of patches which are under Fixes, they
are usually the best people to review the patch. Adding them now.
Signed-off-by: butt3rflyh4ck <redacted>
We'll need your name. AFAIU it's because of Developer Certificate of
Origin. You'll need to resend with this fixed (and please remember the CCs).
From: Pavel Skripkin <hidden> Date: 2021-08-19 19:53:49
On 8/19/21 10:16 PM, Jakub Kicinski wrote:
On Fri, 20 Aug 2021 02:14:58 +0800 butt3rflyh4ck wrote:
quoted
From: butt3rflyh4ck <redacted>
This check was incomplete, did not consider size is 0:
if (len != ALIGN(size, 4) + hdrlen)
goto err;
if size from qrtr_hdr is 0, the result of ALIGN(size, 4)
will be 0, In case of len == hdrlen and size == 0
in header this check won't fail and
if (cb->type == QRTR_TYPE_NEW_SERVER) {
/* Remote node endpoint can bridge other distant nodes */
const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
}
will also read out of bound from data, which is hdrlen allocated block.
Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Fixes: ad9d24c9429e ("net: qrtr: fix OOB Read in qrtr_endpoint_post")
Please make sure to CC authors of patches which are under Fixes, they
are usually the best people to review the patch. Adding them now.
quoted
Signed-off-by: butt3rflyh4ck <redacted>
We'll need your name. AFAIU it's because of Developer Certificate of
Origin. You'll need to resend with this fixed (and please remember the CCs).
I am able to trigger described bug with this repro:
#define _GNU_SOURCE
#include <endian.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
uint64_t r[1] = {0xffffffffffffffff};
int main(void)
{
syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
intptr_t res = 0;
memcpy((void*)0x20000000, "/dev/qrtr-tun\000", 14);
res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000000ul,
0x82ul, 0);
if (res != -1)
r[0] = res;
memcpy((void*)0x20000000,
"\x01\x21\x21\x39\x04\x00\x00\x00\xd6\x2c\xf3\x50"
"\x1a\x47\x56\x52\x19\x56\x86\xef\x00\x00\x00\x00"
"\xff\xff\xff\x00\xfe\xff\xff\xff", 32);
syscall(__NR_write, r[0], 0x20000000ul, 0x20ul);
return 0;
}
( I didn't write it, it's modified syzbot's repro :) )
One thing I am wondering about is why Fixes tag points to my commit? My
commit didn't introduce any bugs, this bug will happen even _without_ my
change.
Anyway, LGTM!
Reviewed-by: Pavel Skripkin <redacted>
With regards,
Pavel Skripkin
Yes, this bug can be triggered without your change. The reason why I
point to your commit is to make it easier for everyone to understand
this bug.
Regards,
Xiaolong Huang (butt3rflyh4ck)
On Fri, Aug 20, 2021 at 3:53 AM Pavel Skripkin [off-list ref] wrote:
On 8/19/21 10:16 PM, Jakub Kicinski wrote:
quoted
On Fri, 20 Aug 2021 02:14:58 +0800 butt3rflyh4ck wrote:
quoted
From: butt3rflyh4ck <redacted>
This check was incomplete, did not consider size is 0:
if (len != ALIGN(size, 4) + hdrlen)
goto err;
if size from qrtr_hdr is 0, the result of ALIGN(size, 4)
will be 0, In case of len == hdrlen and size == 0
in header this check won't fail and
if (cb->type == QRTR_TYPE_NEW_SERVER) {
/* Remote node endpoint can bridge other distant nodes */
const struct qrtr_ctrl_pkt *pkt = data + hdrlen;
qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
}
will also read out of bound from data, which is hdrlen allocated block.
Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Fixes: ad9d24c9429e ("net: qrtr: fix OOB Read in qrtr_endpoint_post")
Please make sure to CC authors of patches which are under Fixes, they
are usually the best people to review the patch. Adding them now.
quoted
Signed-off-by: butt3rflyh4ck <redacted>
We'll need your name. AFAIU it's because of Developer Certificate of
Origin. You'll need to resend with this fixed (and please remember the CCs).
I am able to trigger described bug with this repro:
#define _GNU_SOURCE
#include <endian.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
uint64_t r[1] = {0xffffffffffffffff};
int main(void)
{
syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
intptr_t res = 0;
memcpy((void*)0x20000000, "/dev/qrtr-tun\000", 14);
res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000000ul,
0x82ul, 0);
if (res != -1)
r[0] = res;
memcpy((void*)0x20000000,
"\x01\x21\x21\x39\x04\x00\x00\x00\xd6\x2c\xf3\x50"
"\x1a\x47\x56\x52\x19\x56\x86\xef\x00\x00\x00\x00"
"\xff\xff\xff\x00\xfe\xff\xff\xff", 32);
syscall(__NR_write, r[0], 0x20000000ul, 0x20ul);
return 0;
}
( I didn't write it, it's modified syzbot's repro :) )
One thing I am wondering about is why Fixes tag points to my commit? My
commit didn't introduce any bugs, this bug will happen even _without_ my
change.
Anyway, LGTM!
Reviewed-by: Pavel Skripkin <redacted>
With regards,
Pavel Skripkin
From: Pavel Skripkin <hidden> Date: 2021-08-19 20:24:46
On 8/19/21 11:06 PM, butt3rflyh4ck wrote:
Yes, this bug can be triggered without your change. The reason why I
point to your commit is to make it easier for everyone to understand
this bug.
As I understand, purpose of Fixes: tag is to point to commit where the
bug was introduced. I could be wrong, so it's up to maintainer to decide
is this Fixes: tag is needed or not :)
With regards,
Pavel Skripkin
From: Jakub Kicinski <kuba@kernel.org> Date: 2021-08-19 21:02:38
On Thu, 19 Aug 2021 23:24:39 +0300 Pavel Skripkin wrote:
On 8/19/21 11:06 PM, butt3rflyh4ck wrote:
quoted
Yes, this bug can be triggered without your change. The reason why I
point to your commit is to make it easier for everyone to understand
this bug.
As I understand, purpose of Fixes: tag is to point to commit where the
bug was introduced. I could be wrong, so it's up to maintainer to decide
is this Fixes: tag is needed or not :)
You're right thanks for pointing that out. May it should actually be:
Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing") ?
From: Pavel Skripkin <hidden> Date: 2021-08-19 21:16:12
On 8/20/21 12:02 AM, Jakub Kicinski wrote:
On Thu, 19 Aug 2021 23:24:39 +0300 Pavel Skripkin wrote:
quoted
On 8/19/21 11:06 PM, butt3rflyh4ck wrote:
quoted
Yes, this bug can be triggered without your change. The reason why I
point to your commit is to make it easier for everyone to understand
this bug.
As I understand, purpose of Fixes: tag is to point to commit where the
bug was introduced. I could be wrong, so it's up to maintainer to decide
is this Fixes: tag is needed or not :)
You're right thanks for pointing that out. May it should actually be:
Fixes: 0baa99ee353c ("net: qrtr: Allow non-immediate node routing") ?
Yes, this is correct one. I guess, patch author has chosen 194ccc88297a,
because my commit has same Fixes: tag (wrong one, btw).
With regards,
Pavel Skripkin