[TG3]: Fix array overrun in tg3_read_partno().

Use proper upper limits for the loops and check for all error
conditions.

The problem was noticed by Adrian Bunk.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 8f059b7968bd..06e4f77b0988 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -10212,7 +10212,7 @@ skip_phy_reset:
 static void __devinit tg3_read_partno(struct tg3 *tp)
 {
         unsigned char vpd_data[256];
-        int i;
+        unsigned int i;
         u32 magic;
 
         if (tg3_nvram_read_swab(tp, 0x0, &magic))
@@ -10258,9 +10258,9 @@ static void __devinit tg3_read_partno(struct tg3 *tp)
         }
 
         /* Now parse and find the part number. */
-        for (i = 0; i < 256; ) {
+        for (i = 0; i < 254; ) {
                 unsigned char val = vpd_data[i];
-                int block_end;
+                unsigned int block_end;
 
                 if (val == 0x82 || val == 0x91) {
                         i = (i + 3 +
@@ -10276,21 +10276,26 @@ static void __devinit tg3_read_partno(struct tg3 *tp)
                              (vpd_data[i + 1] +
                               (vpd_data[i + 2] << 8)));
                 i += 3;
-                while (i < block_end) {
+
+                if (block_end > 256)
+                        goto out_not_found;
+
+                while (i < (block_end - 2)) {
                         if (vpd_data[i + 0] == 'P' &&
                             vpd_data[i + 1] == 'N') {
                                 int partno_len = vpd_data[i + 2];
 
-                                if (partno_len > 24)
+                                i += 3;
+                                if (partno_len > 24 || (partno_len + i) > 256)
                                         goto out_not_found;
 
                                 memcpy(tp->board_part_number,
-                                       &vpd_data[i + 3],
-                                       partno_len);
+                                       &vpd_data[i], partno_len);
 
                                 /* Success. */
                                 return;
                         }
+                        i += 3 + vpd_data[i + 2];
                 }
 
                 /* Part number not found. */