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* [dpdk-stable] Fwd: [PATCH v3] lib/rte_rib6: fix stack buffer overflow
       [not found] ` <20210621132834.21673-1-ohilyard@iol.unh.edu>
@ 2021-06-21 13:30   ` Owen Hilyard
  2021-06-23 15:17   ` [dpdk-stable] [PATCH v4] rib: fix max depth IPv6 lookup ohilyard
  1 sibling, 0 replies; 3+ messages in thread
From: Owen Hilyard @ 2021-06-21 13:30 UTC (permalink / raw)
  To: dpdk stable

Sorry about the forward, I forgot to CC stable when I sent it out.

---------- Forwarded message ---------
From: <ohilyard@iol.unh.edu>
Date: Mon, Jun 21, 2021 at 9:28 AM
Subject: [PATCH v3] lib/rte_rib6: fix stack buffer overflow
To: <vladimir.medvedkin@intel.com>
Cc: <dev@dpdk.org>, <stephen@networkplumber.org>, <david.marchand@redhat.com>,
Owen Hilyard <ohilyard@iol.unh.edu>


From: Owen Hilyard <ohilyard@iol.unh.edu>

ASAN found a stack buffer overflow in lib/rib/rte_rib6.c:get_dir.
The fix for the stack buffer overflow was to make sure depth
was always < 128, since when depth = 128 it caused the index
into the ip address to be 16, which read off the end of the array.

While trying to solve the buffer overflow, I noticed that a few
changes could be made to remove the for loop entirely.

Fixes: f7e861e21c ("rib: support IPv6")

Signed-off-by: Owen Hilyard <ohilyard@iol.unh.edu>
---
 lib/rib/rte_rib6.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/lib/rib/rte_rib6.c b/lib/rib/rte_rib6.c
index f6c55ee45..96424e9c9 100644
--- a/lib/rib/rte_rib6.c
+++ b/lib/rib/rte_rib6.c
@@ -79,20 +79,33 @@ is_covered(const uint8_t ip1[RTE_RIB6_IPV6_ADDR_SIZE],
 static inline int
 get_dir(const uint8_t ip[RTE_RIB6_IPV6_ADDR_SIZE], uint8_t depth)
 {
-       int i = 0;
-       uint8_t p_depth, msk;
-
-       for (p_depth = depth; p_depth >= 8; p_depth -= 8)
-               i++;
-
-       msk = 1 << (7 - p_depth);
-       return (ip[i] & msk) != 0;
+       uint8_t index, msk;
+
+       /*
+        * depth & 127 clamps depth to values that will not
+        * read off the end of ip.
+        * depth is the number of bits deep into ip to traverse, and
+        * is incremented in blocks of 8 (1 byte). This means the last
+        * 3 bits are irrelevant to what the index of ip should be.
+        */
+       index = (depth & (UINT8_MAX - 1)) / CHAR_BIT;
+
+       /*
+        * msk is the bitmask used to extract the bit used to decide the
+        * direction of the next step of the binary search.
+        */
+       msk = 1 << (7 - (depth & 7));
+
+       return (ip[index] & msk) != 0;
 }

 static inline struct rte_rib6_node *
 get_nxt_node(struct rte_rib6_node *node,
        const uint8_t ip[RTE_RIB6_IPV6_ADDR_SIZE])
 {
+       if (node->depth == RIB6_MAXDEPTH)
+               return NULL;
+
        return (get_dir(ip, node->depth)) ? node->right : node->left;
 }

-- 
2.30.2

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [dpdk-stable] [PATCH v4] rib: fix max depth IPv6 lookup
       [not found] ` <20210621132834.21673-1-ohilyard@iol.unh.edu>
  2021-06-21 13:30   ` [dpdk-stable] Fwd: [PATCH v3] lib/rte_rib6: fix stack buffer overflow Owen Hilyard
@ 2021-06-23 15:17   ` ohilyard
  2021-06-24 13:23     ` David Marchand
  1 sibling, 1 reply; 3+ messages in thread
From: ohilyard @ 2021-06-23 15:17 UTC (permalink / raw)
  To: vladimir.medvedkin; +Cc: dev, stable, stephen, david.marchand, Owen Hilyard

From: Owen Hilyard <ohilyard@iol.unh.edu>

ASAN found a stack buffer overflow in lib/rib/rte_rib6.c:get_dir.
The fix for the stack buffer overflow was to make sure depth
was always < 128, since when depth = 128 it caused the index
into the ip address to be 16, which read off the end of the array.

While trying to solve the buffer overflow, I noticed that a few
changes could be made to remove the for loop entirely.

Fixes: f7e861e21c ("rib: support IPv6")

Signed-off-by: Owen Hilyard <ohilyard@iol.unh.edu>
---
 lib/rib/rte_rib6.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/lib/rib/rte_rib6.c b/lib/rib/rte_rib6.c
index f6c55ee45..96424e9c9 100644
--- a/lib/rib/rte_rib6.c
+++ b/lib/rib/rte_rib6.c
@@ -79,20 +79,33 @@ is_covered(const uint8_t ip1[RTE_RIB6_IPV6_ADDR_SIZE],
 static inline int
 get_dir(const uint8_t ip[RTE_RIB6_IPV6_ADDR_SIZE], uint8_t depth)
 {
-	int i = 0;
-	uint8_t p_depth, msk;
-
-	for (p_depth = depth; p_depth >= 8; p_depth -= 8)
-		i++;
-
-	msk = 1 << (7 - p_depth);
-	return (ip[i] & msk) != 0;
+	uint8_t index, msk;
+
+	/*
+	 * depth & 127 clamps depth to values that will not
+	 * read off the end of ip.
+	 * depth is the number of bits deep into ip to traverse, and
+	 * is incremented in blocks of 8 (1 byte). This means the last
+	 * 3 bits are irrelevant to what the index of ip should be.
+	 */
+	index = (depth & (UINT8_MAX - 1)) / CHAR_BIT;
+
+	/*
+	 * msk is the bitmask used to extract the bit used to decide the
+	 * direction of the next step of the binary search.
+	 */
+	msk = 1 << (7 - (depth & 7));
+
+	return (ip[index] & msk) != 0;
 }
 
 static inline struct rte_rib6_node *
 get_nxt_node(struct rte_rib6_node *node,
 	const uint8_t ip[RTE_RIB6_IPV6_ADDR_SIZE])
 {
+	if (node->depth == RIB6_MAXDEPTH)
+		return NULL;
+
 	return (get_dir(ip, node->depth)) ? node->right : node->left;
 }
 
-- 
2.30.2


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [dpdk-stable] [PATCH v4] rib: fix max depth IPv6 lookup
  2021-06-23 15:17   ` [dpdk-stable] [PATCH v4] rib: fix max depth IPv6 lookup ohilyard
@ 2021-06-24 13:23     ` David Marchand
  0 siblings, 0 replies; 3+ messages in thread
From: David Marchand @ 2021-06-24 13:23 UTC (permalink / raw)
  To: Owen Hilyard; +Cc: Vladimir Medvedkin, dev, dpdk stable, Stephen Hemminger

On Wed, Jun 23, 2021 at 5:17 PM <ohilyard@iol.unh.edu> wrote:
>
> From: Owen Hilyard <ohilyard@iol.unh.edu>
>
> ASAN found a stack buffer overflow in lib/rib/rte_rib6.c:get_dir.
> The fix for the stack buffer overflow was to make sure depth
> was always < 128, since when depth = 128 it caused the index
> into the ip address to be 16, which read off the end of the array.
>
> While trying to solve the buffer overflow, I noticed that a few
> changes could be made to remove the for loop entirely.
>
> Fixes: f7e861e21c ("rib: support IPv6")
Updated sha1.
Cc: stable@dpdk.org

>
> Signed-off-by: Owen Hilyard <ohilyard@iol.unh.edu>
Acked-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>

Applied, thanks.


-- 
David Marchand


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-06-24 13:23 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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     [not found] <20210616181833.356159-1-ohilyard@iol.unh.edu>
     [not found] ` <20210621132834.21673-1-ohilyard@iol.unh.edu>
2021-06-21 13:30   ` [dpdk-stable] Fwd: [PATCH v3] lib/rte_rib6: fix stack buffer overflow Owen Hilyard
2021-06-23 15:17   ` [dpdk-stable] [PATCH v4] rib: fix max depth IPv6 lookup ohilyard
2021-06-24 13:23     ` David Marchand

patches for DPDK stable branches

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