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| author | Paolo Bonzini <pbonzini@redhat.com> | 2017-06-01 17:18:57 +0200 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2017-08-31 11:51:16 -0500 |
| commit | d016071ca577e32ea9ebc0ed6fa39c8b22cb6788 (patch) | |
| tree | 25cb1bb340565c6eff50f74ad25ed83fb22e45a4 | |
| parent | 20fd62d374659269977426cacd9a655c022ff774 (diff) | |
| download | qemu-d016071ca577e32ea9ebc0ed6fa39c8b22cb6788.tar.gz | |
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>
(cherry picked from commit 24c0c77af515acbf0f9705e8096f33ef24d37430)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.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 1888118e5f..c353118882 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; } |