1eb10f4091
On many systems, the sockaddr_un.sun_path field is quite
small. Even on Linux, it is only 108 characters. A user of
the credential-cache daemon can easily surpass this,
especially if their home directory is in a deep directory
tree (since the default location expands ~/.git-credentials).
We can hack around this in the unix-socket.[ch] code by
doing a chdir() to the enclosing directory, feeding the
relative basename to the socket functions, and then
restoring the working directory.
This introduces several new possible error cases for
creating a socket, including an irrecoverable one in the
case that we can't restore the working directory. In the
case of the credential-cache code, we could perhaps get away
with simply chdir()-ing to the socket directory and never
coming back. However, I'd rather do it at the lower level
for a few reasons:
1. It keeps the hackery behind an opaque interface instead
of polluting the main program logic.
2. A hack in credential-cache won't help any unix-socket
users who come along later.
3. The chdir trickery isn't that likely to fail (basically
it's only a problem if your cwd is missing or goes away
while you're running). And because we only enable the
hack when we get a too-long name, it can only fail in
cases that would have failed under the previous code
anyway.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
118 lines
2.3 KiB
C
118 lines
2.3 KiB
C
#include "cache.h"
|
|
#include "unix-socket.h"
|
|
|
|
static int unix_stream_socket(void)
|
|
{
|
|
int fd = socket(AF_UNIX, SOCK_STREAM, 0);
|
|
if (fd < 0)
|
|
die_errno("unable to create socket");
|
|
return fd;
|
|
}
|
|
|
|
static int chdir_len(const char *orig, int len)
|
|
{
|
|
char *path = xmemdupz(orig, len);
|
|
int r = chdir(path);
|
|
free(path);
|
|
return r;
|
|
}
|
|
|
|
struct unix_sockaddr_context {
|
|
char orig_dir[PATH_MAX];
|
|
};
|
|
|
|
static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
|
|
{
|
|
if (!ctx->orig_dir[0])
|
|
return;
|
|
/*
|
|
* If we fail, we can't just return an error, since we have
|
|
* moved the cwd of the whole process, which could confuse calling
|
|
* code. We are better off to just die.
|
|
*/
|
|
if (chdir(ctx->orig_dir) < 0)
|
|
die("unable to restore original working directory");
|
|
}
|
|
|
|
static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
|
|
struct unix_sockaddr_context *ctx)
|
|
{
|
|
int size = strlen(path) + 1;
|
|
|
|
ctx->orig_dir[0] = '\0';
|
|
if (size > sizeof(sa->sun_path)) {
|
|
const char *slash = find_last_dir_sep(path);
|
|
const char *dir;
|
|
|
|
if (!slash) {
|
|
errno = ENAMETOOLONG;
|
|
return -1;
|
|
}
|
|
|
|
dir = path;
|
|
path = slash + 1;
|
|
size = strlen(path) + 1;
|
|
if (size > sizeof(sa->sun_path)) {
|
|
errno = ENAMETOOLONG;
|
|
return -1;
|
|
}
|
|
|
|
if (!getcwd(ctx->orig_dir, sizeof(ctx->orig_dir))) {
|
|
errno = ENAMETOOLONG;
|
|
return -1;
|
|
}
|
|
if (chdir_len(dir, slash - dir) < 0)
|
|
return -1;
|
|
}
|
|
|
|
memset(sa, 0, sizeof(*sa));
|
|
sa->sun_family = AF_UNIX;
|
|
memcpy(sa->sun_path, path, size);
|
|
return 0;
|
|
}
|
|
|
|
int unix_stream_connect(const char *path)
|
|
{
|
|
int fd;
|
|
struct sockaddr_un sa;
|
|
struct unix_sockaddr_context ctx;
|
|
|
|
if (unix_sockaddr_init(&sa, path, &ctx) < 0)
|
|
return -1;
|
|
fd = unix_stream_socket();
|
|
if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
|
|
unix_sockaddr_cleanup(&ctx);
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
unix_sockaddr_cleanup(&ctx);
|
|
return fd;
|
|
}
|
|
|
|
int unix_stream_listen(const char *path)
|
|
{
|
|
int fd;
|
|
struct sockaddr_un sa;
|
|
struct unix_sockaddr_context ctx;
|
|
|
|
if (unix_sockaddr_init(&sa, path, &ctx) < 0)
|
|
return -1;
|
|
fd = unix_stream_socket();
|
|
|
|
unlink(path);
|
|
if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
|
|
unix_sockaddr_cleanup(&ctx);
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
|
|
if (listen(fd, 5) < 0) {
|
|
unix_sockaddr_cleanup(&ctx);
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
|
|
unix_sockaddr_cleanup(&ctx);
|
|
return fd;
|
|
}
|