140 lines
4.3 KiB
Diff
140 lines
4.3 KiB
Diff
From a8bc90052f18348718412cebf7b569da95bad264 Mon Sep 17 00:00:00 2001
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From: Ben Hutchings <ben@decadent.org.uk>
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Date: Sun, 1 Nov 2015 16:22:53 +0000
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Subject: [PATCH 2/2] ppp, slip: Validate VJ compression slot parameters
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completely
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Currently slhc_init() treats out-of-range values of rslots and tslots
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as equivalent to 0, except that if tslots is too large it will
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dereference a null pointer (CVE-2015-7799).
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Add a range-check at the top of the function and make it return an
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ERR_PTR() on error instead of NULL. Change the callers accordingly.
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Compile-tested only.
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Reported-by: 郭永刚 <guoyonggang@360.cn>
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References: http://article.gmane.org/gmane.comp.security.oss.general/17908
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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drivers/isdn/i4l/isdn_ppp.c | 10 ++++------
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drivers/net/ppp/ppp_generic.c | 6 ++----
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drivers/net/slip/slhc.c | 12 ++++++++----
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drivers/net/slip/slip.c | 2 +-
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4 files changed, 15 insertions(+), 15 deletions(-)
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diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
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index 86f9abebcb72..9c1e8adaf4fc 100644
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--- a/drivers/isdn/i4l/isdn_ppp.c
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+++ b/drivers/isdn/i4l/isdn_ppp.c
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@@ -322,9 +322,9 @@ isdn_ppp_open(int min, struct file *file)
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* VJ header compression init
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*/
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is->slcomp = slhc_init(16, 16); /* not necessary for 2. link in bundle */
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- if (!is->slcomp) {
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+ if (IS_ERR(is->slcomp)) {
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isdn_ppp_ccp_reset_free(is);
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- return -ENOMEM;
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+ return PTR_ERR(is->slcomp);
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}
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#endif
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#ifdef CONFIG_IPPP_FILTER
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@@ -573,10 +573,8 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
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is->maxcid = val;
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#ifdef CONFIG_ISDN_PPP_VJ
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sltmp = slhc_init(16, val);
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- if (!sltmp) {
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- printk(KERN_ERR "ippp, can't realloc slhc struct\n");
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- return -ENOMEM;
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- }
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+ if (IS_ERR(sltmp))
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+ return PTR_ERR(sltmp);
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if (is->slcomp)
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slhc_free(is->slcomp);
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is->slcomp = sltmp;
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diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
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index ed00446759b2..9a863c6a6a33 100644
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--- a/drivers/net/ppp/ppp_generic.c
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+++ b/drivers/net/ppp/ppp_generic.c
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@@ -721,10 +721,8 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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val &= 0xffff;
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}
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vj = slhc_init(val2+1, val+1);
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- if (!vj) {
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- netdev_err(ppp->dev,
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- "PPP: no memory (VJ compressor)\n");
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- err = -ENOMEM;
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+ if (IS_ERR(vj)) {
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+ err = PTR_ERR(vj);
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break;
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}
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ppp_lock(ppp);
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diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
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index 079f7adfcde5..27ed25252aac 100644
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--- a/drivers/net/slip/slhc.c
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+++ b/drivers/net/slip/slhc.c
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@@ -84,8 +84,9 @@ static long decode(unsigned char **cpp);
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static unsigned char * put16(unsigned char *cp, unsigned short x);
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static unsigned short pull16(unsigned char **cpp);
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-/* Initialize compression data structure
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+/* Allocate compression data structure
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* slots must be in range 0 to 255 (zero meaning no compression)
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+ * Returns pointer to structure or ERR_PTR() on error.
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*/
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struct slcompress *
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slhc_init(int rslots, int tslots)
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@@ -94,11 +95,14 @@ slhc_init(int rslots, int tslots)
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register struct cstate *ts;
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struct slcompress *comp;
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+ if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
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+ return ERR_PTR(-EINVAL);
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+
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comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL);
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if (! comp)
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goto out_fail;
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- if ( rslots > 0 && rslots < 256 ) {
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+ if (rslots > 0) {
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size_t rsize = rslots * sizeof(struct cstate);
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comp->rstate = kzalloc(rsize, GFP_KERNEL);
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if (! comp->rstate)
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@@ -106,7 +110,7 @@ slhc_init(int rslots, int tslots)
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comp->rslot_limit = rslots - 1;
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}
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- if ( tslots > 0 && tslots < 256 ) {
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+ if (tslots > 0) {
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size_t tsize = tslots * sizeof(struct cstate);
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comp->tstate = kzalloc(tsize, GFP_KERNEL);
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if (! comp->tstate)
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@@ -141,7 +145,7 @@ out_free2:
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out_free:
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kfree(comp);
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out_fail:
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- return NULL;
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+ return ERR_PTR(-ENOMEM);
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}
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diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
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index 05387b1e2e95..a17d86a57734 100644
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--- a/drivers/net/slip/slip.c
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+++ b/drivers/net/slip/slip.c
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@@ -164,7 +164,7 @@ static int sl_alloc_bufs(struct slip *sl, int mtu)
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if (cbuff == NULL)
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goto err_exit;
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slcomp = slhc_init(16, 16);
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- if (slcomp == NULL)
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+ if (IS_ERR(slcomp))
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goto err_exit;
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#endif
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spin_lock_bh(&sl->lock);
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--
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2.4.3
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