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Rewrote .incbin's parsing and checks for position and size to increase robustness

This commit is contained in:
ggn 2022-12-19 13:09:06 +02:00 committed by Shamus Hammons
parent e6e125acd9
commit 78d0bcae46
1 changed files with 46 additions and 31 deletions
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77
direct.c
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@ -621,32 +621,40 @@ allright:
tok += 2;
size = lseek(fd, 0L, SEEK_END);
pos = lseek(fd, 0L, SEEK_SET);
if (*tok != EOL)
{
// Check size parameter (can be omitted)
if (*tok++ == ',')
// Parse size and position parameters
uint64_t requested_size = -1; // -1 means "not set" for these two
if (*tok++ != ',')
{
close(fd);
return error("expected comma after incbin filename");
}
if (tok != EOL)
{
if (*tok != ',')
{
if (abs_expr(&size) != OK)
if (abs_expr(&requested_size) != OK)
{
close(fd);
return ERROR;
}
if ((int64_t)size <= 0)
if ((int64_t)requested_size <= 0 || requested_size > size)
{
close(fd);
return error("invalid incbin size requested");
}
}
else
size = lseek(fd, 0L, SEEK_END);
}
// Check offset parameter (can be omitted)
if (*tok != EOL)
{
if (*tok++ == ',')
if (*tok != EOL)
{
if (*tok++ != ',')
{
close(fd);
return error("expected comma after size parameter");
}
if (*tok != EOL)
{
if (abs_expr(&pos) != OK)
@ -654,30 +662,37 @@ allright:
close(fd);
return ERROR;
}
lseek(fd, pos, SEEK_SET);
if ((int64_t)(size - pos) < 0)
if ((int64_t)pos <= 0 || pos > size)
{
return error("requested incbin size out of range");
close(fd);
return error("invalid incbin position requested");
}
}
else
{
// offset parameter omitted, so it's 0
pos = lseek(fd, 0L, SEEK_SET);
}
}
else
return error(comma_error);
if (*tok != EOL)
{
close(fd);
return error("extra characters following incbin");
}
}
else
pos = lseek(fd, 0L, SEEK_SET);
}
else
{
// size & pos not given, so assume offset of 0 and all of the binary
size = lseek(fd, 0L, SEEK_END);
pos = lseek(fd, 0L, SEEK_SET);
// Adjust size if the user didn't specify it via the parameter
if (requested_size == -1)
{
requested_size = size - pos;
}
// Are we going to read past the end of the file?
if (pos + requested_size > size)
{
close(fd);
return error("invalid combination of incbin position and size");
}
size = requested_size;
// All checks passed, let's seek to where the user requested, otherwise at file start
lseek(fd, pos, SEEK_SET);
}
chcheck(size);