ppp, slip: Validate VJ compression slot parameters completely (CVE-2015-7799)

Plus a preparatory fix to isdn_ppp.
This commit is contained in:
Ben Hutchings 2015-12-03 00:48:31 +00:00
parent 045f1d7a16
commit 1060c43c3d
4 changed files with 170 additions and 0 deletions

3
debian/changelog vendored
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@ -13,6 +13,9 @@ linux (4.2.6-2) UNRELEASED; urgency=medium
(CVE-2015-7833, partly fixed in 4.2.6-1)
* udeb: Add dm-service-time to multipath-modules (Closes: #806131)
* unix: avoid use-after-free in ep_remove_wait_queue (CVE-2013-7446)
* isdn_ppp: Add checks for allocation failure in isdn_ppp_open()
* ppp, slip: Validate VJ compression slot parameters completely
(CVE-2015-7799)
-- Salvatore Bonaccorso <carnil@debian.org> Tue, 10 Nov 2015 22:05:58 +0100

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@ -0,0 +1,37 @@
From: Ben Hutchings <ben@decadent.org.uk>
Date: Sun, 1 Nov 2015 16:21:24 +0000
Subject: isdn_ppp: Add checks for allocation failure in isdn_ppp_open()
Origin: https://git.kernel.org/linus/0baa57d8dc32db78369d8b5176ef56c5e2e18ab3
Compile-tested only.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/isdn/i4l/isdn_ppp.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index c4198fa..86f9abe 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -301,6 +301,8 @@ isdn_ppp_open(int min, struct file *file)
is->compflags = 0;
is->reset = isdn_ppp_ccp_reset_alloc(is);
+ if (!is->reset)
+ return -ENOMEM;
is->lp = NULL;
is->mp_seqno = 0; /* MP sequence number */
@@ -320,6 +322,10 @@ isdn_ppp_open(int min, struct file *file)
* VJ header compression init
*/
is->slcomp = slhc_init(16, 16); /* not necessary for 2. link in bundle */
+ if (!is->slcomp) {
+ isdn_ppp_ccp_reset_free(is);
+ return -ENOMEM;
+ }
#endif
#ifdef CONFIG_IPPP_FILTER
is->pass_filter = NULL;

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@ -0,0 +1,128 @@
From: Ben Hutchings <ben@decadent.org.uk>
Date: Sun, 1 Nov 2015 16:22:53 +0000
Subject: ppp, slip: Validate VJ compression slot parameters completely
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Origin: https://git.kernel.org/linus/4ab42d78e37a294ac7bc56901d563c642e03c4ae
Currently slhc_init() treats out-of-range values of rslots and tslots
as equivalent to 0, except that if tslots is too large it will
dereference a null pointer (CVE-2015-7799).
Add a range-check at the top of the function and make it return an
ERR_PTR() on error instead of NULL. Change the callers accordingly.
Compile-tested only.
Reported-by: 郭永刚 <guoyonggang@360.cn>
References: http://article.gmane.org/gmane.comp.security.oss.general/17908
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/isdn/i4l/isdn_ppp.c | 10 ++++------
drivers/net/ppp/ppp_generic.c | 6 ++----
drivers/net/slip/slhc.c | 12 ++++++++----
drivers/net/slip/slip.c | 2 +-
4 files changed, 15 insertions(+), 15 deletions(-)
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -322,9 +322,9 @@ isdn_ppp_open(int min, struct file *file
* VJ header compression init
*/
is->slcomp = slhc_init(16, 16); /* not necessary for 2. link in bundle */
- if (!is->slcomp) {
+ if (IS_ERR(is->slcomp)) {
isdn_ppp_ccp_reset_free(is);
- return -ENOMEM;
+ return PTR_ERR(is->slcomp);
}
#endif
#ifdef CONFIG_IPPP_FILTER
@@ -573,10 +573,8 @@ isdn_ppp_ioctl(int min, struct file *fil
is->maxcid = val;
#ifdef CONFIG_ISDN_PPP_VJ
sltmp = slhc_init(16, val);
- if (!sltmp) {
- printk(KERN_ERR "ippp, can't realloc slhc struct\n");
- return -ENOMEM;
- }
+ if (IS_ERR(sltmp))
+ return PTR_ERR(sltmp);
if (is->slcomp)
slhc_free(is->slcomp);
is->slcomp = sltmp;
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -719,10 +719,8 @@ static long ppp_ioctl(struct file *file,
val &= 0xffff;
}
vj = slhc_init(val2+1, val+1);
- if (!vj) {
- netdev_err(ppp->dev,
- "PPP: no memory (VJ compressor)\n");
- err = -ENOMEM;
+ if (IS_ERR(vj)) {
+ err = PTR_ERR(vj);
break;
}
ppp_lock(ppp);
--- a/drivers/net/slip/slhc.c
+++ b/drivers/net/slip/slhc.c
@@ -84,8 +84,9 @@ static long decode(unsigned char **cpp);
static unsigned char * put16(unsigned char *cp, unsigned short x);
static unsigned short pull16(unsigned char **cpp);
-/* Initialize compression data structure
+/* Allocate compression data structure
* slots must be in range 0 to 255 (zero meaning no compression)
+ * Returns pointer to structure or ERR_PTR() on error.
*/
struct slcompress *
slhc_init(int rslots, int tslots)
@@ -94,11 +95,14 @@ slhc_init(int rslots, int tslots)
register struct cstate *ts;
struct slcompress *comp;
+ if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
+ return ERR_PTR(-EINVAL);
+
comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL);
if (! comp)
goto out_fail;
- if ( rslots > 0 && rslots < 256 ) {
+ if (rslots > 0) {
size_t rsize = rslots * sizeof(struct cstate);
comp->rstate = kzalloc(rsize, GFP_KERNEL);
if (! comp->rstate)
@@ -106,7 +110,7 @@ slhc_init(int rslots, int tslots)
comp->rslot_limit = rslots - 1;
}
- if ( tslots > 0 && tslots < 256 ) {
+ if (tslots > 0) {
size_t tsize = tslots * sizeof(struct cstate);
comp->tstate = kzalloc(tsize, GFP_KERNEL);
if (! comp->tstate)
@@ -141,7 +145,7 @@ out_free2:
out_free:
kfree(comp);
out_fail:
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
--- a/drivers/net/slip/slip.c
+++ b/drivers/net/slip/slip.c
@@ -164,7 +164,7 @@ static int sl_alloc_bufs(struct slip *sl
if (cbuff == NULL)
goto err_exit;
slcomp = slhc_init(16, 16);
- if (slcomp == NULL)
+ if (IS_ERR(slcomp))
goto err_exit;
#endif
spin_lock_bh(&sl->lock);

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@ -113,3 +113,5 @@ bugfix/x86/x86-xen-p2m-hint-at-the-last-populated-P2M-entry.patch
bugfix/all/usbvision-fix-overflow-of-interfaces-array.patch
bugfix/all/media-usbvision-fix-crash-on-detecting-device-with-i.patch
bugfix/all/unix-avoid-use-after-free-in-ep_remove_wait_queue.patch
bugfix/all/isdn_ppp-add-checks-for-allocation-failure-in-isdn_p.patch
bugfix/all/ppp-slip-validate-vj-compression-slot-parameters-com.patch