diff options
| author | cinap_lenrek <cinap_lenrek@felloff.net> | 2014-10-12 20:18:59 +0200 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@felloff.net> | 2014-10-12 20:18:59 +0200 |
| commit | cc6ab3189125beb510a0cda836cce2648b8fede5 (patch) | |
| tree | 276ee1819d0b98283ac1570d929f738ea9b6f096 /sys/src/9/pc/memory.c | |
| parent | ca694c51efbcab0e9dd7421f395cfbb4b573b90e (diff) | |
pc: sanity check bda value in lowraminit() to avoid overflow with efi
Diffstat (limited to 'sys/src/9/pc/memory.c')
| -rw-r--r-- | sys/src/9/pc/memory.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/sys/src/9/pc/memory.c b/sys/src/9/pc/memory.c index 8f634c107..851f1b1d7 100644 --- a/sys/src/9/pc/memory.c +++ b/sys/src/9/pc/memory.c @@ -376,7 +376,7 @@ sigsearch(char* signature) static void lowraminit(void) { - ulong n, pa, x; + ulong pa, x; uchar *bda; /* @@ -387,9 +387,11 @@ lowraminit(void) */ x = PADDR(CPU0END); bda = (uchar*)KADDR(0x400); - n = ((bda[0x14]<<8)|bda[0x13])*KB-x; - mapfree(&rmapram, x, n); - memset(KADDR(x), 0, n); /* keep us honest */ + pa = ((bda[0x14]<<8)|bda[0x13])*KB; + if(x < pa){ + mapfree(&rmapram, x, pa-x); + memset(KADDR(x), 0, pa-x); /* keep us honest */ + } x = PADDR(PGROUND((ulong)end)); pa = MemMin; |