52 lines
1.8 KiB
Diff
52 lines
1.8 KiB
Diff
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From c518445f9fddc786f191f4f5926bf483fa2bd1ff Mon Sep 17 00:00:00 2001
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From: Stefan Berger <stefanb@linux.ibm.com>
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Date: Wed, 16 Feb 2022 11:17:47 -0500
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Subject: [PATCH] swtpm: Check header size indicator against expected size (CID
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375869)
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This fix addresses Coverity issue CID 375869 (CVE-2022-23645).
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Check the header size indicated in the header of the state against the
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expected size and return an error code in case the header size indicator
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is different. There was only one header size so far since blobheader was
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introduced, so we don't need to deal with different sizes.
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Without this fix a specially crafted header could cause out-of-bounds
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accesses on the byte array containing the swtpm's state.
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Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
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---
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src/swtpm/swtpm_nvfile.c | 11 ++++++++++-
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1 file changed, 10 insertions(+), 1 deletion(-)
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diff --git a/src/swtpm/swtpm_nvfile.c b/src/swtpm/swtpm_nvfile.c
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index dc7cfbf1..0efb9da8 100644
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--- a/src/swtpm/swtpm_nvfile.c
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+++ b/src/swtpm/swtpm_nvfile.c
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@@ -1260,6 +1260,7 @@ SWTPM_NVRAM_CheckHeader(unsigned char *data, uint32_t length,
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uint8_t *hdrversion, bool quiet)
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{
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blobheader *bh = (blobheader *)data;
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+ uint16_t hdrsize;
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if (length < sizeof(bh)) {
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if (!quiet)
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@@ -1285,8 +1286,16 @@ SWTPM_NVRAM_CheckHeader(unsigned char *data, uint32_t length,
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return TPM_BAD_VERSION;
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}
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+ hdrsize = ntohs(bh->hdrsize);
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+ if (hdrsize != sizeof(blobheader)) {
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+ logprintf(STDERR_FILENO,
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+ "bad header size: %u != %zu\n",
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+ hdrsize, sizeof(blobheader));
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+ return TPM_BAD_DATASIZE;
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+ }
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+
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*hdrversion = bh->version;
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- *dataoffset = ntohs(bh->hdrsize);
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+ *dataoffset = hdrsize;
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*hdrflags = ntohs(bh->flags);
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return TPM_SUCCESS;
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