From: Philippe Mathieu-Daudé <f4bug@amsat.org>
Date: Wed, 4 Apr 2018 23:32:38 +0000 (-0300)
Subject: hw/block/pflash_cfi: fix off-by-one error
X-Git-Tag: qemu-xen-4.11.1^2~67
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=44633a272b58cd03eecddd6c224e73f2a52e7ca1;p=qemu-xen.git

hw/block/pflash_cfi: fix off-by-one error

ASAN reported:

    hw/block/pflash_cfi02.c:245:33: runtime error: index 82 out of bounds for type 'uint8_t [82]'

Since the 'cfi_len' member is not used, remove it to keep the code safer.

Cc: qemu-stable@nongnu.org
Reported-by: AddressSanitizer
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 07c13a71721d9f8c690b66752964e254af247475)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 1113ab1ccf..2e8284001d 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -90,7 +90,6 @@ struct pflash_t {
     uint16_t ident1;
     uint16_t ident2;
     uint16_t ident3;
-    uint8_t cfi_len;
     uint8_t cfi_table[0x52];
     uint64_t counter;
     unsigned int writeblock_size;
@@ -153,7 +152,7 @@ static uint32_t pflash_cfi_query(pflash_t *pfl, hwaddr offset)
     boff = offset >> (ctz32(pfl->bank_width) +
                       ctz32(pfl->max_device_width) - ctz32(pfl->device_width));
 
-    if (boff > pfl->cfi_len) {
+    if (boff >= sizeof(pfl->cfi_table)) {
         return 0;
     }
     /* Now we will construct the CFI response generated by a single
@@ -385,10 +384,10 @@ static uint32_t pflash_read (pflash_t *pfl, hwaddr offset,
                 boff = boff >> 2;
             }
 
-            if (boff > pfl->cfi_len) {
-                ret = 0;
-            } else {
+            if (boff < sizeof(pfl->cfi_table)) {
                 ret = pfl->cfi_table[boff];
+            } else {
+                ret = 0;
             }
         } else {
             /* If we have a read larger than the bank_width, combine multiple
@@ -791,7 +790,6 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp)
     pfl->cmd = 0;
     pfl->status = 0;
     /* Hardcoded CFI table */
-    pfl->cfi_len = 0x52;
     /* Standard "QRY" string */
     pfl->cfi_table[0x10] = 'Q';
     pfl->cfi_table[0x11] = 'R';
diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index c81ddd3a99..75d1ae1026 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -83,7 +83,6 @@ struct pflash_t {
     uint16_t ident3;
     uint16_t unlock_addr0;
     uint16_t unlock_addr1;
-    uint8_t cfi_len;
     uint8_t cfi_table[0x52];
     QEMUTimer *timer;
     /* The device replicates the flash memory across its memory space.  Emulate
@@ -235,10 +234,11 @@ static uint32_t pflash_read (pflash_t *pfl, hwaddr offset,
         break;
     case 0x98:
         /* CFI query mode */
-        if (boff > pfl->cfi_len)
-            ret = 0;
-        else
+        if (boff < sizeof(pfl->cfi_table)) {
             ret = pfl->cfi_table[boff];
+        } else {
+            ret = 0;
+        }
         break;
     }
 
@@ -663,7 +663,6 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
     pfl->cmd = 0;
     pfl->status = 0;
     /* Hardcoded CFI table (mostly from SG29 Spansion flash) */
-    pfl->cfi_len = 0x52;
     /* Standard "QRY" string */
     pfl->cfi_table[0x10] = 'Q';
     pfl->cfi_table[0x11] = 'R';