* [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
@ 2015-12-22 13:07 P J P
2015-12-22 13:36 ` Jiri Pirko
2015-12-22 14:46 ` Paolo Bonzini
0 siblings, 2 replies; 7+ messages in thread
From: P J P @ 2015-12-22 13:07 UTC (permalink / raw)
To: qemu-devel; +Cc: Qinghao Tang, Jiri Pirko, Scott Feldman
Hello Scott, Jiri
A stack overflow issue was reported by Mr Qinghao Tang, CC'd here. It occurs
while processing transmit(tx) descriptors in tx_consume() routine. If a
descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX=16) packet
fragments, the processing loop suffers an off-by-one error. Thus leading to
OOB memory access and leakage of host memory.
Please see below a proposed patch to fix this issue. Does it look okay?
===
>From f3461d8098a0572786f5a2d7a492863090c73134 Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Tue, 22 Dec 2015 18:21:00 +0530
Subject: [PATCH] net: rocker: fix an incorrect array bounds check
While processing transmit(tx) descriptors in 'tx_consume' routine
the switch emulator suffers from an off-by-one error, if a
descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX)
fragments. Fix an incorrect bounds check to avoid it.
Reported-by: Qinghao Tang <luodalongde@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
hw/net/rocker/rocker.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
index c57f1a6..05102bd 100644
--- a/hw/net/rocker/rocker.c
+++ b/hw/net/rocker/rocker.c
@@ -245,7 +245,7 @@ static int tx_consume(Rocker *r, DescInfo *info)
goto err_bad_io;
}
- if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
+ if (++iovcnt >= ROCKER_TX_FRAGS_MAX) {
goto err_too_many_frags;
}
}
--
2.4.3
===
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
2015-12-22 13:07 [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check P J P
@ 2015-12-22 13:36 ` Jiri Pirko
2015-12-22 14:45 ` P J P
2015-12-22 14:46 ` Paolo Bonzini
1 sibling, 1 reply; 7+ messages in thread
From: Jiri Pirko @ 2015-12-22 13:36 UTC (permalink / raw)
To: P J P; +Cc: Qinghao Tang, Scott Feldman, qemu-devel
Tue, Dec 22, 2015 at 02:07:01PM CET, ppandit@redhat.com wrote:
> Hello Scott, Jiri
>
>A stack overflow issue was reported by Mr Qinghao Tang, CC'd here. It occurs
>while processing transmit(tx) descriptors in tx_consume() routine. If a
>descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX=16) packet
>fragments, the processing loop suffers an off-by-one error. Thus leading to
>OOB memory access and leakage of host memory.
>
>Please see below a proposed patch to fix this issue. Does it look okay?
>
>===
>From f3461d8098a0572786f5a2d7a492863090c73134 Mon Sep 17 00:00:00 2001
>From: Prasad J Pandit <pjp@fedoraproject.org>
>Date: Tue, 22 Dec 2015 18:21:00 +0530
>Subject: [PATCH] net: rocker: fix an incorrect array bounds check
>
>While processing transmit(tx) descriptors in 'tx_consume' routine
>the switch emulator suffers from an off-by-one error, if a
>descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX)
>fragments. Fix an incorrect bounds check to avoid it.
>
>Reported-by: Qinghao Tang <luodalongde@gmail.com>
>Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
2015-12-22 13:36 ` Jiri Pirko
@ 2015-12-22 14:45 ` P J P
0 siblings, 0 replies; 7+ messages in thread
From: P J P @ 2015-12-22 14:45 UTC (permalink / raw)
To: Jiri Pirko; +Cc: Qinghao Tang, Scott Feldman, qemu-devel, qemu-stable
+-- On Tue, 22 Dec 2015, Jiri Pirko wrote --+
| >From f3461d8098a0572786f5a2d7a492863090c73134 Mon Sep 17 00:00:00 2001
| >From: Prasad J Pandit <pjp@fedoraproject.org>
| >Date: Tue, 22 Dec 2015 18:21:00 +0530
| >Subject: [PATCH] net: rocker: fix an incorrect array bounds check
| >
| >While processing transmit(tx) descriptors in 'tx_consume' routine
| >the switch emulator suffers from an off-by-one error, if a
| >descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX)
| >fragments. Fix an incorrect bounds check to avoid it.
| >
| >Reported-by: Qinghao Tang <luodalongde@gmail.com>
| >Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
|
| Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Thank you. (CC'd qemu-stable for 2.5)
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
2015-12-22 13:07 [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check P J P
2015-12-22 13:36 ` Jiri Pirko
@ 2015-12-22 14:46 ` Paolo Bonzini
2015-12-22 17:26 ` P J P
1 sibling, 1 reply; 7+ messages in thread
From: Paolo Bonzini @ 2015-12-22 14:46 UTC (permalink / raw)
To: P J P, qemu-devel; +Cc: Qinghao Tang, Scott Feldman, Jiri Pirko
On 22/12/2015 14:07, P J P wrote:
> Hello Scott, Jiri
>
> A stack overflow issue was reported by Mr Qinghao Tang, CC'd here. It
> occurs while processing transmit(tx) descriptors in tx_consume()
> routine. If a descriptor was to have more than
> allowed(ROCKER_TX_FRAGS_MAX=16) packet fragments, the processing loop
> suffers an off-by-one error. Thus leading to OOB memory access and
> leakage of host memory.
>
> Please see below a proposed patch to fix this issue. Does it look okay?
>
> ===
> From f3461d8098a0572786f5a2d7a492863090c73134 Mon Sep 17 00:00:00 2001
> From: Prasad J Pandit <pjp@fedoraproject.org>
> Date: Tue, 22 Dec 2015 18:21:00 +0530
> Subject: [PATCH] net: rocker: fix an incorrect array bounds check
>
> While processing transmit(tx) descriptors in 'tx_consume' routine
> the switch emulator suffers from an off-by-one error, if a
> descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX)
> fragments. Fix an incorrect bounds check to avoid it.
>
> Reported-by: Qinghao Tang <luodalongde@gmail.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
> hw/net/rocker/rocker.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
> index c57f1a6..05102bd 100644
> --- a/hw/net/rocker/rocker.c
> +++ b/hw/net/rocker/rocker.c
> @@ -245,7 +245,7 @@ static int tx_consume(Rocker *r, DescInfo *info)
> goto err_bad_io;
> }
>
> - if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
> + if (++iovcnt >= ROCKER_TX_FRAGS_MAX) {
Doesn't this forbid some valid ROCKER_TX_FRAGS_MAX-element iovecs? The
check should be moved before the assignment to iov[iovcnt].iov_len.
Paolo
> goto err_too_many_frags;
> }
> }
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
2015-12-22 14:46 ` Paolo Bonzini
@ 2015-12-22 17:26 ` P J P
2015-12-22 18:13 ` Paolo Bonzini
0 siblings, 1 reply; 7+ messages in thread
From: P J P @ 2015-12-22 17:26 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: Qinghao Tang, Scott Feldman, Jiri Pirko, qemu-devel
+-- On Tue, 22 Dec 2015, Paolo Bonzini wrote --+
| > - if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
| > + if (++iovcnt >= ROCKER_TX_FRAGS_MAX) {
|
| Doesn't this forbid some valid ROCKER_TX_FRAGS_MAX-element iovecs?
forbid..? Sorry, I did not get the question.
| The check should be moved before the assignment to iov[iovcnt].iov_len.
You mean like below..?
===
diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
index c57f1a6..2e77e50 100644
--- a/hw/net/rocker/rocker.c
+++ b/hw/net/rocker/rocker.c
@@ -232,6 +232,9 @@ static int tx_consume(Rocker *r, DescInfo *info)
frag_addr = rocker_tlv_get_le64(tlvs[ROCKER_TLV_TX_FRAG_ATTR_ADDR]);
frag_len = rocker_tlv_get_le16(tlvs[ROCKER_TLV_TX_FRAG_ATTR_LEN]);
+ if (iovcnt >= ROCKER_TX_FRAGS_MAX) {
+ goto err_too_many_frags;
+ }
iov[iovcnt].iov_len = frag_len;
iov[iovcnt].iov_base = g_malloc(frag_len);
if (!iov[iovcnt].iov_base) {
@@ -244,10 +247,7 @@ static int tx_consume(Rocker *r, DescInfo *info)
err = -ROCKER_ENXIO;
goto err_bad_io;
}
-
- if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
- goto err_too_many_frags;
- }
+ iovcnt++;
}
if (iovcnt) {
===
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
2015-12-22 17:26 ` P J P
@ 2015-12-22 18:13 ` Paolo Bonzini
2015-12-22 19:04 ` P J P
0 siblings, 1 reply; 7+ messages in thread
From: Paolo Bonzini @ 2015-12-22 18:13 UTC (permalink / raw)
To: P J P; +Cc: Qinghao Tang, Jiri Pirko, Scott Feldman, qemu-devel
On 22/12/2015 18:26, P J P wrote:
> +-- On Tue, 22 Dec 2015, Paolo Bonzini wrote --+
> | > - if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
> | > + if (++iovcnt >= ROCKER_TX_FRAGS_MAX) {
> |
> | Doesn't this forbid some valid ROCKER_TX_FRAGS_MAX-element iovecs?
>
> forbid..? Sorry, I did not get the question.
>
> | The check should be moved before the assignment to iov[iovcnt].iov_len.
>
> You mean like below..?
>
> ===
> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
> index c57f1a6..2e77e50 100644
> --- a/hw/net/rocker/rocker.c
> +++ b/hw/net/rocker/rocker.c
> @@ -232,6 +232,9 @@ static int tx_consume(Rocker *r, DescInfo *info)
> frag_addr = rocker_tlv_get_le64(tlvs[ROCKER_TLV_TX_FRAG_ATTR_ADDR]);
> frag_len = rocker_tlv_get_le16(tlvs[ROCKER_TLV_TX_FRAG_ATTR_LEN]);
>
> + if (iovcnt >= ROCKER_TX_FRAGS_MAX) {
> + goto err_too_many_frags;
> + }
> iov[iovcnt].iov_len = frag_len;
> iov[iovcnt].iov_base = g_malloc(frag_len);
> if (!iov[iovcnt].iov_base) {
> @@ -244,10 +247,7 @@ static int tx_consume(Rocker *r, DescInfo *info)
> err = -ROCKER_ENXIO;
> goto err_bad_io;
> }
> -
> - if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
> - goto err_too_many_frags;
> - }
> + iovcnt++;
> }
>
> if (iovcnt) {
> ===
>
> Thank you.
> --
> Prasad J Pandit / Red Hat Product Security Team
> 47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
>
>
Yes, can you submit it as v2?
Paolo
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check
2015-12-22 18:13 ` Paolo Bonzini
@ 2015-12-22 19:04 ` P J P
0 siblings, 0 replies; 7+ messages in thread
From: P J P @ 2015-12-22 19:04 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: Qinghao Tang, Jiri Pirko, Scott Feldman, qemu-devel
+-- On Tue, 22 Dec 2015, Paolo Bonzini wrote --+
| > ===
| > diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
| > index c57f1a6..2e77e50 100644
| > --- a/hw/net/rocker/rocker.c
| > +++ b/hw/net/rocker/rocker.c
| > @@ -232,6 +232,9 @@ static int tx_consume(Rocker *r, DescInfo *info)
| > frag_addr = rocker_tlv_get_le64(tlvs[ROCKER_TLV_TX_FRAG_ATTR_ADDR]);
| > frag_len = rocker_tlv_get_le16(tlvs[ROCKER_TLV_TX_FRAG_ATTR_LEN]);
| >
| > + if (iovcnt >= ROCKER_TX_FRAGS_MAX) {
| > + goto err_too_many_frags;
| > + }
| > iov[iovcnt].iov_len = frag_len;
| > iov[iovcnt].iov_base = g_malloc(frag_len);
| > if (!iov[iovcnt].iov_base) {
| > @@ -244,10 +247,7 @@ static int tx_consume(Rocker *r, DescInfo *info)
| > err = -ROCKER_ENXIO;
| > goto err_bad_io;
| > }
| > -
| > - if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
| > - goto err_too_many_frags;
| > - }
| > + iovcnt++;
| > }
| >
| > if (iovcnt) {
| > ===
|
| Yes, can you submit it as v2?
Sure, okay. But I don't get the difference.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
^ permalink raw reply [flat|nested] 7+ messages in thread
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2015-12-22 13:07 [Qemu-devel] [PATCH] net: rocker: fix an incorrect array bounds check P J P
2015-12-22 13:36 ` Jiri Pirko
2015-12-22 14:45 ` P J P
2015-12-22 14:46 ` Paolo Bonzini
2015-12-22 17:26 ` P J P
2015-12-22 18:13 ` Paolo Bonzini
2015-12-22 19:04 ` P J P
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