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| author | Paolo Bonzini <pbonzini@redhat.com> | 2017-06-01 17:18:57 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-06-15 11:04:05 +0200 |
| commit | 24c0c77af515acbf0f9705e8096f33ef24d37430 (patch) | |
| tree | 77144f2d0675ef1a54e7c7e7a0ea967718cdb53c | |
| parent | 134550bf81a026e18cf58b81e2c2cceaf516f92e (diff) | |
| download | qemu-24c0c77af515acbf0f9705e8096f33ef24d37430.zip qemu-24c0c77af515acbf0f9705e8096f33ef24d37430.tar.gz qemu-24c0c77af515acbf0f9705e8096f33ef24d37430.tar.bz2 | |
megasas: do not read iovec count more than once from frame
Avoid TOC-TOU bugs depending on how the compiler behaves.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | hw/scsi/megasas.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c index 1888118..c353118 100644 --- a/hw/scsi/megasas.c +++ b/hw/scsi/megasas.c @@ -675,15 +675,16 @@ out: static int megasas_map_dcmd(MegasasState *s, MegasasCmd *cmd) { dma_addr_t iov_pa, iov_size; + int iov_count; cmd->flags = le16_to_cpu(cmd->frame->header.flags); - if (!cmd->frame->header.sge_count) { + iov_count = cmd->frame->header.sge_count; + if (!iov_count) { trace_megasas_dcmd_zero_sge(cmd->index); cmd->iov_size = 0; return 0; - } else if (cmd->frame->header.sge_count > 1) { - trace_megasas_dcmd_invalid_sge(cmd->index, - cmd->frame->header.sge_count); + } else if (iov_count > 1) { + trace_megasas_dcmd_invalid_sge(cmd->index, iov_count); cmd->iov_size = 0; return -EINVAL; } |