48 lines
2.0 KiB
Diff
48 lines
2.0 KiB
Diff
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Reference: bsc#961692 CVE-2016-1714
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When processing firmware configurations, an OOB r/w access occurs
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if 's->cur_entry' is set to be invalid(FW_CFG_INVALID=0xffff).
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Add a check to validate 's->cur_entry' to avoid such access.
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Reported-by: Donghai Zdh <address@hidden>
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Signed-off-by: Prasad J Pandit <address@hidden>
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---
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hw/nvram/fw_cfg.c | 12 ++++++++----
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1 file changed, 8 insertions(+), 4 deletions(-)
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Updated as per review in
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-> https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg00398.html
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Index: xen-4.6.0-testing/tools/qemu-xen-traditional-dir-remote/hw/fw_cfg.c
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===================================================================
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--- xen-4.6.0-testing.orig/tools/qemu-xen-traditional-dir-remote/hw/fw_cfg.c
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+++ xen-4.6.0-testing/tools/qemu-xen-traditional-dir-remote/hw/fw_cfg.c
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@@ -54,11 +54,15 @@ typedef struct _FWCfgState {
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static void fw_cfg_write(FWCfgState *s, uint8_t value)
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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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FW_CFG_DPRINTF("write %d\n", value);
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- if (s->cur_entry & FW_CFG_WRITE_CHANNEL && s->cur_offset < e->len) {
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+ if (s->cur_entry & FW_CFG_WRITE_CHANNEL
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+ && e != NULL
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+ && e->callback
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+ && s->cur_offset < e->len) {
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e->data[s->cur_offset++] = value;
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if (s->cur_offset == e->len) {
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e->callback(e->callback_opaque, e->data);
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@@ -88,7 +92,8 @@ static int fw_cfg_select(FWCfgState *s,
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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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