Revision e1d911dd4c7b76a5a8cec0f5c8de15981e34da83 authored by Johannes Schindelin on 12 September 2019, 12:54:05 UTC, committed by Johannes Schindelin on 04 December 2019, 12:20:05 UTC
The backslash character is not a valid part of a file name on Windows. Hence it is dangerous to allow writing files that were unpacked from tree objects, when the stored file name contains a backslash character: it will be misinterpreted as directory separator. This not only causes ambiguity when a tree contains a blob `a\b` and a tree `a` that contains a blob `b`, but it also can be used as part of an attack vector to side-step the careful protections against writing into the `.git/` directory during a clone of a maliciously-crafted repository. Let's prevent that, addressing CVE-2019-1354. Note: we guard against backslash characters in tree objects' file names _only_ on Windows (because on other platforms, even on those where NTFS volumes can be mounted, the backslash character is _not_ a directory separator), and _only_ when `core.protectNTFS = true` (because users might need to generate tree objects for other platforms, of course without touching the worktree, e.g. using `git update-index --cacheinfo`). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent 0060fd1
sigchain.c
#include "cache.h"
#include "sigchain.h"
#define SIGCHAIN_MAX_SIGNALS 32
struct sigchain_signal {
sigchain_fun *old;
int n;
int alloc;
};
static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
static void check_signum(int sig)
{
if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
die("BUG: signal out of range: %d", sig);
}
int sigchain_push(int sig, sigchain_fun f)
{
struct sigchain_signal *s = signals + sig;
check_signum(sig);
ALLOC_GROW(s->old, s->n + 1, s->alloc);
s->old[s->n] = signal(sig, f);
if (s->old[s->n] == SIG_ERR)
return -1;
s->n++;
return 0;
}
int sigchain_pop(int sig)
{
struct sigchain_signal *s = signals + sig;
check_signum(sig);
if (s->n < 1)
return 0;
if (signal(sig, s->old[s->n - 1]) == SIG_ERR)
return -1;
s->n--;
return 0;
}
void sigchain_push_common(sigchain_fun f)
{
sigchain_push(SIGINT, f);
sigchain_push(SIGHUP, f);
sigchain_push(SIGTERM, f);
sigchain_push(SIGQUIT, f);
sigchain_push(SIGPIPE, f);
}
void sigchain_pop_common(void)
{
sigchain_pop(SIGPIPE);
sigchain_pop(SIGQUIT);
sigchain_pop(SIGTERM);
sigchain_pop(SIGHUP);
sigchain_pop(SIGINT);
}
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