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Fix corner cases in readlink() usage.

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Make sure all calls are protected by HAVE_READLINK, and get the buffer
overflow tests right.  Be a bit more paranoid about string length in
_tarWriteHeader(), too.
This commit is contained in:
Tom Lane
2011-12-07 13:34:19 -05:00
parent 9c32da5caa
commit 85d85ff7ef
1 changed files with 38 additions and 14 deletions
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52
src/backend/replication/basebackup.c
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@ -46,7 +46,7 @@ static int64 sendDir(char *path, int basepathlen, bool sizeonly);
static void sendFile(char *readfilename, char *tarfilename,
struct stat * statbuf);
static void sendFileWithContent(const char *filename, const char *content);
static void _tarWriteHeader(const char *filename, char *linktarget,
static void _tarWriteHeader(const char *filename, const char *linktarget,
struct stat * statbuf);
static void send_int8_string(StringInfoData *buf, int64 intval);
static void SendBackupHeader(List *tablespaces);
@ -117,17 +117,19 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
snprintf(fullpath, sizeof(fullpath), "pg_tblspc/%s", de->d_name);
#if defined(HAVE_READLINK) || defined(WIN32)
rllen = readlink(fullpath, linkpath, sizeof(linkpath) - 1);
rllen = readlink(fullpath, linkpath, sizeof(linkpath));
if (rllen < 0)
{
ereport(WARNING,
(errmsg("could not read symbolic link \"%s\": %m", fullpath)));
(errmsg("could not read symbolic link \"%s\": %m",
fullpath)));
continue;
}
else if (rllen >= sizeof(linkpath))
{
ereport(WARNING,
(errmsg("symbolic link \"%s\" target is too long", fullpath)));
(errmsg("symbolic link \"%s\" target is too long",
fullpath)));
continue;
}
linkpath[rllen] = '\0';
@ -139,9 +141,9 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
tablespaces = lappend(tablespaces, ti);
#else
/*
* If the platform does not have symbolic links, it should not be possible
* to have tablespaces - clearly somebody else created them. Warn about it
* and ignore.
* If the platform does not have symbolic links, it should not be
* possible to have tablespaces - clearly somebody else created
* them. Warn about it and ignore.
*/
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
@ -635,24 +637,45 @@ sendDir(char *path, int basepathlen, bool sizeonly)
continue; /* don't recurse into pg_xlog */
}
/* Allow symbolic links in pg_tblspc only */
if (strcmp(path, "./pg_tblspc") == 0 &&
#ifndef WIN32
if (S_ISLNK(statbuf.st_mode) && strcmp(path, "./pg_tblspc") == 0)
S_ISLNK(statbuf.st_mode)
#else
if (pgwin32_is_junction(pathbuf) && strcmp(path, "./pg_tblspc") == 0)
pgwin32_is_junction(pathbuf)
#endif
)
{
/* Allow symbolic links in pg_tblspc */
#if defined(HAVE_READLINK) || defined(WIN32)
char linkpath[MAXPGPATH];
int rllen;
MemSet(linkpath, 0, sizeof(linkpath));
if (readlink(pathbuf, linkpath, sizeof(linkpath) - 1) == -1)
rllen = readlink(pathbuf, linkpath, sizeof(linkpath));
if (rllen < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read symbolic link \"%s\": %m",
pathbuf)));
if (rllen >= sizeof(linkpath))
ereport(ERROR,
(errmsg("symbolic link \"%s\" target is too long",
pathbuf)));
linkpath[rllen] = '\0';
if (!sizeonly)
_tarWriteHeader(pathbuf + basepathlen + 1, linkpath, &statbuf);
size += 512; /* Size of the header just added */
#else
/*
* If the platform does not have symbolic links, it should not be
* possible to have tablespaces - clearly somebody else created
* them. Warn about it and ignore.
*/
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablespaces are not supported on this platform")));
continue;
#endif /* HAVE_READLINK */
}
else if (S_ISDIR(statbuf.st_mode))
{
@ -800,7 +823,8 @@ sendFile(char *readfilename, char *tarfilename, struct stat * statbuf)
static void
_tarWriteHeader(const char *filename, char *linktarget, struct stat * statbuf)
_tarWriteHeader(const char *filename, const char *linktarget,
struct stat * statbuf)
{
char h[512];
int lastSum = 0;
@ -848,7 +872,7 @@ _tarWriteHeader(const char *filename, char *linktarget, struct stat * statbuf)
{
/* Type - Symbolic link */
sprintf(&h[156], "2");
strcpy(&h[157], linktarget);
sprintf(&h[157], "%.99s", linktarget);
}
else if (S_ISDIR(statbuf->st_mode))
/* Type - directory */