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authorBen Hutchings <ben@decadent.org.uk>2015-11-01 16:22:53 +0000
committerBen Hutchings <ben@decadent.org.uk>2015-12-30 02:26:04 +0000
commitdf085f1cb3acd3d75408ff94f366983873bce7d2 (patch)
tree13934519845dd48d0dfe6b3a08b372fbc6e8cdd6
parent3ed88ba9e848aac74ae150b089ed36c25016faca (diff)
ppp, slip: Validate VJ compression slot parameters completely
commit 4ab42d78e37a294ac7bc56901d563c642e03c4ae upstream. 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> [bwh: Backported to 3.2: adjust indentation]
-rw-r--r--drivers/isdn/i4l/isdn_ppp.c10
-rw-r--r--drivers/net/ppp/ppp_generic.c6
-rw-r--r--drivers/net/slip/slhc.c12
-rw-r--r--drivers/net/slip/slip.c2
4 files changed, 15 insertions, 15 deletions
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index 0033bca19ffc..3604aa725014 100644
--- 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
@@ -574,10 +574,8 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
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;
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 4782d79f21c0..82d44215bb33 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -703,10 +703,8 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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);
diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
index 0a0a6643cf3a..042425ec086c 100644
--- a/drivers/net/slip/slhc.c
+++ b/drivers/net/slip/slhc.c
@@ -85,8 +85,9 @@ 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)
@@ -95,11 +96,14 @@ 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)
@@ -107,7 +111,7 @@ 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)
@@ -142,7 +146,7 @@ out_free2:
out_free:
kfree(comp);
out_fail:
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
index ba08341fb92c..1a6e2eac2de6 100644
--- a/drivers/net/slip/slip.c
+++ b/drivers/net/slip/slip.c
@@ -164,7 +164,7 @@ static int sl_alloc_bufs(struct slip *sl, int mtu)
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);