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Fix size_t overflow in Malloc() argument in ReadParams() #77

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Merged
mcarbonneaux merged 1 commit into from
Nov 26, 2025
Merged

Fix size_t overflow in Malloc() argument in ReadParams() #77

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13 changes: 10 additions & 3 deletions libfcgi/fcgiapp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
#include <memory.h> /* for memchr() */
#include <stdarg.h>
#include <stdio.h>
#include <stdint.h>
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@LeSpocky LeSpocky Nov 26, 2025 •
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This introduces an implicit dependency to at least C99.

Link: https://en.cppreference.com/w/c/header/stdint.html

#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
Expand Down Expand Up @@ -1160,6 +1161,7 @@ char *FCGX_GetParam(const char *name, FCGX_ParamArray envp)
static int ReadParams(Params *paramsPtr, FCGX_Stream *stream)
{
int nameLen, valueLen;
size_t totalLen;
unsigned char lenBuff[3];
char *nameValue;

Expand All @@ -1175,7 +1177,7 @@ static int ReadParams(Params *paramsPtr, FCGX_Stream *stream)
}
nameLen = ((nameLen & 0x7f) << 24) + (lenBuff[0] << 16)
+ (lenBuff[1] << 8) + lenBuff[2];
if (nameLen >= INT_MAX) {
if (nameLen >= INT_MAX || nameLen >= SIZE_MAX) {
SetError(stream, FCGX_PARAMS_ERROR);
return -1;
}
Expand All @@ -1191,16 +1193,21 @@ static int ReadParams(Params *paramsPtr, FCGX_Stream *stream)
}
valueLen = ((valueLen & 0x7f) << 24) + (lenBuff[0] << 16)
+ (lenBuff[1] << 8) + lenBuff[2];
if (valueLen >= INT_MAX) {
if (valueLen >= INT_MAX || valueLen >= SIZE_MAX) {
SetError(stream, FCGX_PARAMS_ERROR);
return -1;
}
}
totalLen = (size_t)nameLen + (size_t)valueLen + 2u;
if (totalLen < (size_t)nameLen || totalLen < (size_t)valueLen) {
SetError(stream, FCGX_PARAMS_ERROR);
return -1;
}
/*
* nameLen and valueLen are now valid; read the name and value
* from stream and construct a standard environment entry.
*/
nameValue = (char *)Malloc(nameLen + valueLen + 2);
nameValue = (char *)Malloc(totalLen);
if(FCGX_GetStr(nameValue, nameLen, stream) != nameLen) {
SetError(stream, FCGX_PARAMS_ERROR);
free(nameValue);
Expand Down