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 66f8fd9dda
)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
stable-2.5
parent
091af18104
commit
020282d3e6
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@ -270,7 +270,8 @@ static int fw_cfg_select(FWCfgState *s, uint16_t key)
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static uint8_t fw_cfg_read(FWCfgState *s)
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{
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int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL);
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FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
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FWCfgEntry *e = (s->cur_entry == FW_CFG_INVALID) ? NULL :
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&s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
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uint8_t ret;
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if (s->cur_entry == FW_CFG_INVALID || !e->data || s->cur_offset >= e->len)
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@ -338,7 +339,8 @@ static void fw_cfg_dma_transfer(FWCfgState *s)
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}
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arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL);
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e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
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e = (s->cur_entry == FW_CFG_INVALID) ? NULL :
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&s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
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if (dma.control & FW_CFG_DMA_CTL_READ) {
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read = 1;
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