42/42_EXT_05_computorv1
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add protection agains big vla

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hugogogo
2026-05-26 15:25:41 +02:00
parent 487191c516
commit 858d4f3ac8
3 changed files with 10 additions and 10 deletions
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4
headers/computorv1.h
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@@ -13,9 +13,9 @@
*/
#define DOUBLE_PRECISION 0.00001
// maximum exponent supported to avoid excessive variable-length stack allocation (VLA),
// maximum size supported to avoid excessive variable-length stack allocation (VLA),
// which can lead to stack overflows, segmentation faults, and potential denial-of-service (DoS)
#define MAX_EXPONENT 1024
#define MAX_VLA_SIZE 1024
/** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* MAIN.C

10
src/launcher.c
View File

@@ -62,8 +62,8 @@ static int get_number_of_exponents(s_term *terms, int max_exponent)
int i;
int nbr_of_exponent;
if (max_exponent <= 0 || max_exponent > MAX_EXPONENT)
stop_errors("max_exponent should be between 0 and %d, but got : %d\n", MAX_EXPONENT, max_exponent);
if (max_exponent <= 0 || max_exponent > MAX_VLA_SIZE)
stop_errors("max_exponent should be between 1 and %d, but got : %d\n", MAX_VLA_SIZE, max_exponent);
int exponent_present[max_exponent];
ft_bzero(exponent_present, sizeof(exponent_present));
@@ -103,6 +103,8 @@ void launch_computorv1(char *input)
// lexerize
token_len = ft_strlen(input) + 1; // +1 for last END token
print_debug("\n-> tokens[%i]\n", token_len);
if (token_len <= 0 || token_len > MAX_VLA_SIZE)
stop_errors("token_len should be between 1 and %d, but got : %d\n", MAX_VLA_SIZE, token_len);
s_token tokens[token_len];
tokens_g_err = tokens;
ft_bzero(tokens, sizeof(tokens));
@@ -111,6 +113,8 @@ void launch_computorv1(char *input)
// parse
terms_count_prediction = count_any_of(input, "-+=") + 2; // +1 for first term that can have no leading '+', +1 for last term == NULL
print_debug("-> terms[%i]\n\n", terms_count_prediction);
if (terms_count_prediction <= 0 || terms_count_prediction > MAX_VLA_SIZE)
stop_errors("terms_count_prediction should be between 1 and %d, but got : %d\n", MAX_VLA_SIZE, terms_count_prediction);
s_term terms[terms_count_prediction];
terms_g_err = terms;
ft_bzero(terms, sizeof(terms));
@@ -121,6 +125,8 @@ void launch_computorv1(char *input)
print_debug("-> max_exponent: %i\n\n", max_exponent);
nbr_of_exponents = get_number_of_exponents(terms, max_exponent);
print_debug("-> nbr_of_exponents: %i\n\n", nbr_of_exponents);
if (nbr_of_exponents <= 0 || nbr_of_exponents > MAX_VLA_SIZE)
stop_errors("nbr_of_exponents should be between 1 and %d, but got : %d\n", MAX_VLA_SIZE, nbr_of_exponents);
s_polynom polynom[nbr_of_exponents + 2]; // +1 for last term, +1 for the degree (eg. degree 2 means 3 terms)
polynom_g_err = polynom;
ft_bzero(polynom, sizeof(polynom));

6
src/parser.c
View File

@@ -194,12 +194,6 @@ static int get_exponent(s_token *tokens, int i, int *token_count)
ret_exponent = 0;
}
// check if exponent is not too big
if (ret_exponent > MAX_EXPONENT)
{
stop_errors("exponent is too big (max supported exponent is %d), got : %d\n", MAX_EXPONENT, ret_exponent);
}
return ret_exponent;
}