Truncate strings in tarCreateHeader() with strlcpy(), not sprintf().

This supplements the GNU libc bug #6530 workarounds introduced in commit
54cd4f04576833abc394e131288bf3dd7dcf4806.  On affected systems, a
tar-format pg_basebackup failed when some filename beneath the data
directory was not valid character data in the postmaster/walsender
locale.  Back-patch to 9.1, where pg_basebackup was introduced.  Extant,
bug-prone conversion specifications receive only ASCII bytes or involve
low-importance messages.

diff --git a/src/port/tar.c b/src/port/tar.c
index 09fd6c10d34e0c576b8fadc1dc06cd3656db5249..d664f6440b33a98567e190c441686d80e69b25b5 100644 (file)
--- a/src/port/tar.c
+++ b/src/port/tar.c
@@ -62,7 +62,7 @@ tarCreateHeader(char *h, const char *filename, const char *linktarget,
        memset(h, 0, 512);                      /* assume tar header size */
 
        /* Name 100 */
-       sprintf(&h[0], "%.99s", filename);
+       strlcpy(&h[0], filename, 100);
        if (linktarget != NULL || S_ISDIR(mode))
        {
                /*
@@ -104,7 +104,7 @@ tarCreateHeader(char *h, const char *filename, const char *linktarget,
                /* Type - Symbolic link */
                sprintf(&h[156], "2");
                /* Link Name 100 */
-               sprintf(&h[157], "%.99s", linktarget);
+               strlcpy(&h[157], linktarget, 100);
        }
        else if (S_ISDIR(mode))
                /* Type - directory */
@@ -121,11 +121,11 @@ tarCreateHeader(char *h, const char *filename, const char *linktarget,
 
        /* User 32 */
        /* XXX: Do we need to care about setting correct username? */
-       sprintf(&h[265], "%.31s", "postgres");
+       strlcpy(&h[265], "postgres", 32);
 
        /* Group 32 */
        /* XXX: Do we need to care about setting correct group name? */
-       sprintf(&h[297], "%.31s", "postgres");
+       strlcpy(&h[297], "postgres", 32);
 
        /* Major Dev 8 */
        sprintf(&h[329], "%07o ", 0);