From 93036f97d3b6da59fadc2aab57401e42e9fc148f Mon Sep 17 00:00:00 2001 Message-ID: <93036f97d3b6da59fadc2aab57401e42e9fc148f.1707394627.git.jdenemar@redhat.com> From: Peter Krempa Date: Mon, 29 Jan 2024 23:33:07 +0100 Subject: [PATCH] virPCIVPDReadVPDBytes: Refactor error handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Each caller was checking that the function read as many bytes as it expected. Move the check inside virPCIVPDReadVPDBytes and make it report a proper error rather than just a combination of VIR_DEBUG inside the function and a random VIR_INFO in the caller. Signed-off-by: Peter Krempa Reviewed-by: Ján Tomko (cherry picked from commit c15a495902bab43454341361174c8ba3dadfcdd5) https://issues.redhat.com/browse/RHEL-22314 [9.4.0] --- src/util/virpcivpd.c | 73 +++++++++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 35 deletions(-) diff --git a/src/util/virpcivpd.c b/src/util/virpcivpd.c index 0021a88f2d..10cabff0b9 100644 --- a/src/util/virpcivpd.c +++ b/src/util/virpcivpd.c @@ -361,34 +361,40 @@ virPCIVPDResourceUpdateKeyword(virPCIVPDResource *res, * @offset: The offset at which bytes need to be read. * @csum: A pointer to a byte containing the current checksum value. Mutated by this function. * - * Returns: the number of VPD bytes read from the specified file descriptor. The csum value is + * Returns 0 if exactly @count bytes were read from @vpdFileFd. The csum value is * also modified as bytes are read. If an error occurs while reading data from the VPD file - * descriptor, it is reported and -1 is returned to the caller. If EOF is occurred, 0 is returned - * to the caller. + * descriptor, it is reported and -1 is returned to the caller. */ -static size_t -virPCIVPDReadVPDBytes(int vpdFileFd, uint8_t *buf, size_t count, off_t offset, uint8_t *csum) +static int +virPCIVPDReadVPDBytes(int vpdFileFd, + uint8_t *buf, + size_t count, + off_t offset, + uint8_t *csum) { ssize_t numRead = pread(vpdFileFd, buf, count, offset); - if (numRead == -1) { - VIR_DEBUG("Unable to read %zu bytes at offset %zd from fd: %d", - count, (ssize_t)offset, vpdFileFd); - } else if (numRead) { - /* - * Update the checksum for every byte read. Per the PCI(e) specs - * the checksum is correct if the sum of all bytes in VPD from - * VPD address 0 up to and including the VPD-R RV field's first - * data byte is zero. - */ - while (count--) { - *csum += *buf; - buf++; - } + if (numRead != count) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("failed to read the PCI VPD data")); + return -1; + } + + /* + * Update the checksum for every byte read. Per the PCI(e) specs + * the checksum is correct if the sum of all bytes in VPD from + * VPD address 0 up to and including the VPD-R RV field's first + * data byte is zero. + */ + while (count--) { + *csum += *buf; + buf++; } - return numRead; + + return 0; } + /** * virPCIVPDParseVPDLargeResourceFields: * @vpdFileFd: A file descriptor associated with a file containing PCI device VPD. @@ -423,12 +429,9 @@ virPCIVPDParseVPDLargeResourceFields(int vpdFileFd, uint16_t resPos, uint16_t re g_autofree char *fieldValue = NULL; /* Keyword resources consist of keywords (2 ASCII bytes per the spec) and 1-byte length. */ - if (virPCIVPDReadVPDBytes(vpdFileFd, buf, 3, fieldPos, csum) != 3) { - /* Invalid field encountered which means the resource itself is invalid too. Report - * That VPD has invalid format and bail. */ - VIR_INFO("Could not read a resource field header - VPD has invalid format"); + if (virPCIVPDReadVPDBytes(vpdFileFd, buf, 3, fieldPos, csum) < 0) return false; - } + fieldDataLen = buf[2]; /* Change the position to the field's data portion skipping the keyword and length bytes. */ fieldPos += 3; @@ -474,10 +477,10 @@ virPCIVPDParseVPDLargeResourceFields(int vpdFileFd, uint16_t resPos, uint16_t re VIR_INFO("A field data length violates the resource length boundary."); return false; } - if (virPCIVPDReadVPDBytes(vpdFileFd, buf, bytesToRead, fieldPos, csum) != bytesToRead) { - VIR_INFO("Could not parse a resource field data - VPD has invalid format"); + + if (virPCIVPDReadVPDBytes(vpdFileFd, buf, bytesToRead, fieldPos, csum) < 0) return false; - } + /* Advance the position to the first byte of the next field. */ fieldPos += fieldDataLen; @@ -566,10 +569,9 @@ virPCIVPDParseVPDLargeResourceString(int vpdFileFd, uint16_t resPos, /* The resource value is not NULL-terminated so add one more byte. */ g_autofree char *buf = g_malloc0(resDataLen + 1); - if (virPCIVPDReadVPDBytes(vpdFileFd, (uint8_t *)buf, resDataLen, resPos, csum) != resDataLen) { - VIR_INFO("Could not read a part of a resource - VPD has invalid format"); + if (virPCIVPDReadVPDBytes(vpdFileFd, (uint8_t *)buf, resDataLen, resPos, csum) < 0) return false; - } + resValue = g_strdup(g_strstrip(buf)); if (!virPCIVPDResourceIsValidTextValue(resValue)) { VIR_INFO("The string resource has invalid characters in its value"); @@ -610,8 +612,8 @@ virPCIVPDParse(int vpdFileFd) while (resPos <= PCI_VPD_ADDR_MASK) { /* Read the resource data type tag. */ - if (virPCIVPDReadVPDBytes(vpdFileFd, &tag, 1, resPos, &csum) != 1) - break; + if (virPCIVPDReadVPDBytes(vpdFileFd, &tag, 1, resPos, &csum) < 0) + return NULL; /* 0x80 == 0b10000000 - the large resource data type flag. */ if (tag & PCI_VPD_LARGE_RESOURCE_FLAG) { @@ -620,9 +622,10 @@ virPCIVPDParse(int vpdFileFd) * where the end tag should be. */ break; } + /* Read the two length bytes of the large resource record. */ - if (virPCIVPDReadVPDBytes(vpdFileFd, headerBuf, 2, resPos + 1, &csum) != 2) - break; + if (virPCIVPDReadVPDBytes(vpdFileFd, headerBuf, 2, resPos + 1, &csum) < 0) + return NULL; resDataLen = headerBuf[0] + (headerBuf[1] << 8); /* Change the position to the byte following the tag and length bytes. */ -- 2.43.0