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oss-fuzz - fixing overread/write when unpacking pe files #927

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Merged
val-ms merged 1 commit into from
Jun 12, 2023
Merged

oss-fuzz - fixing overread/write when unpacking pe files #927

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18 changes: 12 additions & 6 deletions libclamav/wwunpack.c
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Original file line number Diff line number Diff line change
Expand Up @@ -231,19 +231,25 @@ cl_error_t wwunpack(uint8_t *exe, uint32_t exesz, uint8_t *wwsect, struct cli_ex
}

if (CL_SUCCESS == error) {
if (pe + 6 > exesz || pe + 7 > exesz || pe + 0x28 > exesz ||
pe + 0x50 > exesz || pe + 0x14 > exesz)
return CL_EFORMAT;

exe[pe + 6] = (uint8_t)scount;
exe[pe + 7] = (uint8_t)(scount >> 8);
if (!CLI_ISCONTAINED(wwsect, sects[scount].rsz, wwsect + 0x295, 4))

if (!CLI_ISCONTAINED(wwsect, sects[scount].rsz, wwsect + 0x295, 4)) {
cli_dbgmsg("WWPack: unpack memory address out of bounds.\n");
return CL_EFORMAT;
}
cli_writeint32(&exe[pe + 0x28], cli_readint32(wwsect + 0x295) + sects[scount].rva + 0x299);

if (!CLI_ISCONTAINED(exe, exesz, exe + pe + 0x50, 4)) {
cli_dbgmsg("WWPack: unpack memory address out of bounds.\n");
else
cli_writeint32(&exe[pe + 0x28], cli_readint32(wwsect + 0x295) + sects[scount].rva + 0x299);
return CL_EFORMAT;
}
cli_writeint32(&exe[pe + 0x50], cli_readint32(&exe[pe + 0x50]) - sects[scount].vsz);

// Bounds check not required here, because we know exesz > pe + 0x50 + 4
structs = &exe[(0xffff & cli_readint32(&exe[pe + 0x14])) + pe + 0x18];

for (i = 0; i < scount; i++) {
if (!CLI_ISCONTAINED(exe, exesz, structs, 0x28)) {
cli_dbgmsg("WWPack: structs pointer out of bounds\n");
Expand Down