diff options
| author | Gabriel L. Somlo <somlo@cmu.edu> | 2015-11-05 09:32:50 -0500 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2016-03-17 16:45:24 -0500 |
| commit | 020282d3e640051405cfd246921413a894ce1dc1 (patch) | |
| tree | f4e9b92f01a90072f69024b9d81c3e7ec7391bbe | |
| parent | 091af181047623695b7239cd8ddf928e1327b6a5 (diff) | |
fw_cfg: avoid calculating invalid current entry pointer
When calculating a pointer to the currently selected fw_cfg item, the
following is used:
FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
When s->cur_entry is FW_CFG_INVALID, we are calculating the address of
a non-existent element in s->entries[arch][...], which is undefined.
This patch ensures the resulting entry pointer is set to NULL whenever
s->cur_entry is FW_CFG_INVALID.
Reported-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Message-id: 1446733972-1602-5-git-send-email-somlo@cmu.edu
Cc: Marc Marí <markmb@redhat.com>
Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 66f8fd9dda312191b78d2a2ba2848bcee76127a2)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | hw/nvram/fw_cfg.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 73b0a813a7..117809bea0 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -270,7 +270,8 @@ static int fw_cfg_select(FWCfgState *s, uint16_t key) static uint8_t fw_cfg_read(FWCfgState *s) { int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL); - FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; + FWCfgEntry *e = (s->cur_entry == FW_CFG_INVALID) ? NULL : + &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; uint8_t ret; if (s->cur_entry == FW_CFG_INVALID || !e->data || s->cur_offset >= e->len) @@ -338,7 +339,8 @@ static void fw_cfg_dma_transfer(FWCfgState *s) } arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL); - e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; + e = (s->cur_entry == FW_CFG_INVALID) ? NULL : + &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; if (dma.control & FW_CFG_DMA_CTL_READ) { read = 1; |