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

[ppisar]

There were still two issues after commit
b0eabca (Update fcgiapp.c, Fixing an integer overflow (CVE-2025-23016)):

• Signed int overflow in "nameLen + valueLen + 2" expression.

• Sizes of size_t and int types are in general unrelated.

This fix resolves both of the issues.

Related to CVE-2025-23016.
Resolve #67.

[LeSpocky]

This introduces an implicit dependency to at least C99.

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

[LeSpocky]

I'm not familiar with autotools, but shouldn't that new dependency somehow be reflected by the build system?

[mcarbonneaux]

I'm not familiar with autotools, but shouldn't that new dependency somehow be reflected by the build system?

the build action seem to work.

but i have now the warning:

fcgiapp.c:1180:47: warning: comparison of integer expressions of different signedness: 'int' and 'long unsigned int' [-Wsign-compare]
 1180 |             if (nameLen >= INT_MAX || nameLen >= SIZE_MAX) {
      |                                               ^~
fcgiapp.c:1196:49: warning: comparison of integer expressions of different signedness: 'int' and 'long unsigned int' [-Wsign-compare]
 1196 |             if (valueLen >= INT_MAX || valueLen >= SIZE_MAX) {
      |                                                 ^~

@ppisar ppisar i think nameLen and valueLen must be size_t in place of int that are plateform depedente.

[ppisar]

Of course the types used in this function are badly chosen. I'm glad you have find it out.

But don't forget that you won't escape the comparison: FCGX_GetChar() returns int, so you need to validate the range when assigning its return value to size_t and then when accumulating nameLen from the bytes.

By the way the signed comparison warning comes from the fact that your standard library defines the SIZE_MAX constant value with LU suffix.

Another option would be simply type-casting nameLen to uintmax_t in the comparison ((uintmax_t)nameLen >= SIZE_MAX) as the nameLen value cannot be negative.