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Revision b3118bdc91876cbc04b7e81dcf7bea71d86ce4f8 authored by Shawn O. Pearce on 14 October 2009, 14:23:51 UTC, committed by Junio C Hamano on 14 October 2009, 20:39:37 UTC 
sha1_file: Fix infinite loop when pack is corrupted
 
Some types of corruption to a pack may confuse the deflate stream
which stores an object.  In Andy's reported case a 36 byte region
of the pack was overwritten, leading to what appeared to be a valid
deflate stream that was trying to produce a result larger than our
allocated output buffer could accept.

Z_BUF_ERROR is returned from inflate() if either the input buffer
needs more input bytes, or the output buffer has run out of space.
Previously we only considered the former case, as it meant we needed
to move the stream's input buffer to the next window in the pack.

We now abort the loop if inflate() returns Z_BUF_ERROR without
consuming the entire input buffer it was given, or has filled
the entire output buffer but has not yet returned Z_STREAM_END.
Either state is a clear indicator that this loop is not working
as expected, and should not continue.

This problem cannot occur with loose objects as we open the entire
loose object as a single buffer and treat Z_BUF_ERROR as an error.

Reported-by: Andy Isaacson <adi@hexapodia.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 583371a
Raw File
walker.h 
#ifndef WALKER_H
#define WALKER_H

#include "remote.h"

struct walker {
	void *data;
	int (*fetch_ref)(struct walker *, struct ref *ref);
	void (*prefetch)(struct walker *, unsigned char *sha1);
	int (*fetch)(struct walker *, unsigned char *sha1);
	void (*cleanup)(struct walker *);
	int get_tree;
	int get_history;
	int get_all;
	int get_verbosely;
	int get_recover;

	int corrupt_object_found;
};

/* Report what we got under get_verbosely */
void walker_say(struct walker *walker, const char *, const char *);

/* Load pull targets from stdin */
int walker_targets_stdin(char ***target, const char ***write_ref);

/* Free up loaded targets */
void walker_targets_free(int targets, char **target, const char **write_ref);

/* If write_ref is set, the ref filename to write the target value to. */
/* If write_ref_log_details is set, additional text will appear in the ref log. */
int walker_fetch(struct walker *impl, int targets, char **target,
		 const char **write_ref, const char *write_ref_log_details);

void walker_free(struct walker *walker);

struct walker *get_http_walker(const char *url, struct remote *remote);

#endif /* WALKER_H */
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