Revision 447ac906e189535e77dcb1f4bbe3f1bc917d4c12 authored by Patrick Steinhardt on 01 December 2022, 14:45:31 UTC, committed by Junio C Hamano on 05 December 2022, 06:14:16 UTC
The `struct attr_stack` tracks the stack of all patterns together with
their attributes. When parsing a gitattributes file that has more than
2^31 such patterns though we may trigger multiple out-of-bounds reads on
64 bit platforms. This is because while the `num_matches` variable is an
unsigned integer, we always use a signed integer to iterate over them.

I have not been able to reproduce this issue due to memory constraints
on my systems. But despite the out-of-bounds reads, the worst thing that
can seemingly happen is to call free(3P) with a garbage pointer when
calling `attr_stack_free()`.

Fix this bug by using unsigned integers to iterate over the array. While
this makes the iteration somewhat awkward when iterating in reverse, it
is at least better than knowingly running into an out-of-bounds read.
While at it, convert the call to `ALLOC_GROW` to use `ALLOC_GROW_BY`
instead.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 34ace8b
Raw File
urlmatch.h
#ifndef URL_MATCH_H
#define URL_MATCH_H

#include "string-list.h"

struct url_info {
	/* normalized url on success, must be freed, otherwise NULL */
	char *url;
	/* if !url, a brief reason for the failure, otherwise NULL */
	const char *err;

	/* the rest of the fields are only set if url != NULL */

	size_t url_len;		/* total length of url (which is now normalized) */
	size_t scheme_len;	/* length of scheme name (excluding final :) */
	size_t user_off;	/* offset into url to start of user name (0 => none) */
	size_t user_len;	/* length of user name; if user_off != 0 but
				   user_len == 0, an empty user name was given */
	size_t passwd_off;	/* offset into url to start of passwd (0 => none) */
	size_t passwd_len;	/* length of passwd; if passwd_off != 0 but
				   passwd_len == 0, an empty passwd was given */
	size_t host_off;	/* offset into url to start of host name (0 => none) */
	size_t host_len;	/* length of host name;
				 * file urls may have host_len == 0 */
	size_t port_off;	/* offset into url to start of port number (0 => none) */
	size_t port_len;	/* if a portnum is present (port_off != 0), it has
				 * this length (excluding the leading ':') starting
				 * from port_off (always 0 for file urls) */
	size_t path_off;	/* offset into url to the start of the url path;
				 * this will always point to a '/' character
				 * after the url has been normalized */
	size_t path_len;	/* length of path portion excluding any trailing
				 * '?...' and '#...' portion; will always be >= 1 */
};

char *url_normalize(const char *, struct url_info *);

struct urlmatch_item {
	size_t hostmatch_len;
	size_t pathmatch_len;
	char user_matched;
};

struct urlmatch_config {
	struct string_list vars;
	struct url_info url;
	const char *section;
	const char *key;

	void *cb;
	int (*collect_fn)(const char *var, const char *value, void *cb);
	int (*cascade_fn)(const char *var, const char *value, void *cb);
	/*
	 * Compare the two matches, the one just discovered and the existing
	 * best match and return a negative value if the found item is to be
	 * rejected or a non-negative value if it is to be accepted.  If this
	 * field is set to NULL, use the default comparison technique, which
	 * checks to ses if found is better (according to the urlmatch
	 * specificity rules) than existing.
	 */
	int (*select_fn)(const struct urlmatch_item *found, const struct urlmatch_item *existing);
	/*
	 * An optional callback to allow e.g. for partial URLs; it shall
	 * return 1 or 0 depending whether `url` matches or not.
	 */
	int (*fallback_match_fn)(const char *url, void *cb);
};

int urlmatch_config_entry(const char *var, const char *value, void *cb);

#endif /* URL_MATCH_H */
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