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Clean up end_option(), and fix a possible off-by-one in the bound check.

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This commit is contained in:
Nicholas J. Kain 2010-11-14 07:50:21 -05:00
parent 5a38e49a81
commit ba553e5d94
2 changed files with 6 additions and 7 deletions
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11
ndhc/options.c
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@ -116,17 +116,16 @@ uint8_t* get_option(struct dhcpMessage *packet, int code)
} }
/* return the position of the 'end' option */ /* return the position of the 'end' option */
int end_option(unsigned char *optionptr) int end_option(uint8_t *optionptr)
{ {
int i = 0; int i = 0;
while (i < DHCP_OPTIONS_BUFSIZE && optionptr[i] != DHCP_END) { while (i < DHCP_OPTIONS_BUFSIZE && optionptr[i] != DHCP_END) {
if (optionptr[i] == DHCP_PADDING) if (optionptr[i] != DHCP_PADDING)
++i; i += optionptr[i + OPT_LEN] + OPT_DATA - 1;
else i++;
i += optionptr[i + OPT_LEN] + 2;
} }
return (i < DHCP_OPTIONS_BUFSIZE ? i : DHCP_OPTIONS_BUFSIZE); return (i < DHCP_OPTIONS_BUFSIZE - 1 ? i : DHCP_OPTIONS_BUFSIZE - 1);
} }

2
ndhc/options.h
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@ -31,7 +31,7 @@ extern struct dhcp_option options[];
extern int option_lengths[]; extern int option_lengths[];
uint8_t *get_option(struct dhcpMessage *packet, int code); uint8_t *get_option(struct dhcpMessage *packet, int code);
int end_option(unsigned char *optionptr); int end_option(uint8_t *optionptr);
int add_option_string(unsigned char *optionptr, unsigned char *string); int add_option_string(unsigned char *optionptr, unsigned char *string);
int add_simple_option(unsigned char *optionptr, unsigned char code, uint32_t data); int add_simple_option(unsigned char *optionptr, unsigned char code, uint32_t data);
struct option_set *find_option(struct option_set *opt_list, char code); struct option_set *find_option(struct option_set *opt_list, char code);