[syslinux:master] chain/partiter: call notsane_gpt_hdr() per header

[syslinux-bot for Michal Soltys]

Commit-ID:  1d09bc044a3aea7edf15caf28dd71308137c57e4
Gitweb:     http://www.syslinux.org/commit/1d09bc044a3aea7edf15caf28dd71308137c57e4
Author:     Michal Soltys <soltys at ziu.info>
AuthorDate: Wed, 26 Nov 2014 00:56:09 +0100
Committer:  Gene Cumm <gene.cumm at gmail.com>
CommitDate: Sun, 15 Mar 2015 04:38:56 -0400

chain/partiter: call notsane_gpt_hdr() per header

Instead of calling it just once after the examination of both headers
(the 2nd one only if necessary) - call it per each header during
examination.

Thus in unlikely situation of passing crc check on primary gpt header
and at the same time failing sanity checks, it will also try backup
header.

Signed-off-by: Michal Soltys <soltys at ziu.info>

---
 com32/chain/partiter.c | 96 +++++++++++++++++++++++++-------------------------
 1 file changed, 48 insertions(+), 48 deletions(-)

diff --git a/com32/chain/partiter.c b/com32/chain/partiter.c
index d570d93..287205f 100644
--- a/com32/chain/partiter.c
+++ b/com32/chain/partiter.c
@@ -528,6 +528,40 @@ void pi_del(struct part_iter **_iter)
     *_iter = NULL;
 }
 
+static int notsane_gpt_hdr(const struct disk_info *di, const struct disk_gpt_header *gpth, int flags)
+{
+    uint64_t gpt_loff;	    /* offset to GPT partition list in sectors */
+    uint64_t gpt_lsiz;	    /* size of GPT partition list in bytes */
+    uint64_t gpt_lcnt;	    /* size of GPT partition in sectors */
+    uint64_t gpt_sec;	    /* secondary gpt header */
+
+    if (!(flags & PIF_STRICT))
+	return 0;
+
+    if (gpth->lba_alt < gpth->lba_cur)
+	gpt_sec = gpth->lba_cur;
+    else
+	gpt_sec = gpth->lba_alt;
+    gpt_loff = gpth->lba_table;
+    gpt_lsiz = (uint64_t)gpth->part_size * gpth->part_count;
+    gpt_lcnt = (gpt_lsiz + di->bps - 1) / di->bps;
+
+    /*
+     * disk_read_sectors allows reading of max 255 sectors, so we use
+     * it as a sanity check base. EFI doesn't specify max (AFAIK).
+     */
+    if (gpt_loff < 2 || !gpt_lsiz || gpt_lcnt > 255u ||
+	    gpth->lba_first_usable > gpth->lba_last_usable ||
+	    !sane(gpt_loff, gpt_lcnt) ||
+	    (gpt_loff + gpt_lcnt > gpth->lba_first_usable && gpt_loff <= gpth->lba_last_usable) ||
+	     gpt_loff + gpt_lcnt > gpt_sec ||
+	    ((flags & PIF_STRICTER) && (gpt_sec >= di->lbacnt)) ||
+	    gpth->part_size < sizeof(struct disk_gpt_part_entry))
+	return -1;
+
+    return 0;
+}
+
 static void try_gpt_we(const char *str, int sec)
 {
     if (sec)
@@ -536,26 +570,31 @@ static void try_gpt_we(const char *str, int sec)
 	warn(str);
 }
 
-static struct disk_gpt_header *try_gpt_hdr(const struct disk_info *di, int sec)
+static struct disk_gpt_header *try_gpt_hdr(const struct disk_info *di, int sec, int flags)
 {
     const char *desc = sec ? "backup" : "primary";
     uint64_t gpt_cur = sec ? di->lbacnt - 1 : 1;
     struct disk_gpt_header *gpth;
-    char errbuf[64];
+    char errbuf[96];
 
     gpth = disk_read_sectors(di, gpt_cur, 1);
     if (!gpth) {
 	sprintf(errbuf, "Unable to read %s GPT header.", desc);
-	try_gpt_we(errbuf, sec);
-	return NULL;
+	goto out;
     }
     if(!valid_crc_hdr(gpth)) {
 	sprintf(errbuf, "Invalid checksum of %s GPT header.", desc);
-	try_gpt_we(errbuf, sec);
-	free(gpth);
-	return NULL;
+	goto out;
+    }
+    if(notsane_gpt_hdr(di, gpth, flags)) {
+	sprintf(errbuf, "Checksum of %s GPT header is valid, but values fail sanity checks.", desc);
+	goto out;
     }
     return gpth;
+out:
+    try_gpt_we(errbuf, sec);
+    free(gpth);
+    return NULL;
 }
 
 static struct disk_gpt_part_entry *try_gpt_list(const struct disk_info *di, const struct disk_gpt_header *gpth, int alt)
@@ -596,40 +635,6 @@ static struct disk_gpt_part_entry *try_gpt_list(const struct disk_info *di, cons
     return gptl;
 }
 
-static int notsane_gpt_hdr(const struct disk_info *di, const struct disk_gpt_header *gpth, int flags)
-{
-    uint64_t gpt_loff;	    /* offset to GPT partition list in sectors */
-    uint64_t gpt_lsiz;	    /* size of GPT partition list in bytes */
-    uint64_t gpt_lcnt;	    /* size of GPT partition in sectors */
-    uint64_t gpt_sec;	    /* secondary gpt header */
-
-    if (!(flags & PIF_STRICT))
-	return 0;
-
-    if (gpth->lba_alt < gpth->lba_cur)
-	gpt_sec = gpth->lba_cur;
-    else
-	gpt_sec = gpth->lba_alt;
-    gpt_loff = gpth->lba_table;
-    gpt_lsiz = (uint64_t)gpth->part_size * gpth->part_count;
-    gpt_lcnt = (gpt_lsiz + di->bps - 1) / di->bps;
-
-    /*
-     * disk_read_sectors allows reading of max 255 sectors, so we use
-     * it as a sanity check base. EFI doesn't specify max (AFAIK).
-     */
-    if (gpt_loff < 2 || !gpt_lsiz || gpt_lcnt > 255u ||
-	    gpth->lba_first_usable > gpth->lba_last_usable ||
-	    !sane(gpt_loff, gpt_lcnt) ||
-	    (gpt_loff + gpt_lcnt > gpth->lba_first_usable && gpt_loff <= gpth->lba_last_usable) ||
-	     gpt_loff + gpt_lcnt > gpt_sec ||
-	    ((flags & PIF_STRICTER) && (gpt_sec >= di->lbacnt)) ||
-	    gpth->part_size < sizeof(struct disk_gpt_part_entry))
-	return -1;
-
-    return 0;
-}
-
 /* pi_begin() - validate and and get proper iterator for a disk described by di */
 struct part_iter *pi_begin(const struct disk_info *di, int flags)
 {
@@ -664,13 +669,13 @@ struct part_iter *pi_begin(const struct disk_info *di, int flags)
 
     /* Try to read GPT header */
     if (isgpt) {
-	gpth = try_gpt_hdr(di, 0);
+	gpth = try_gpt_hdr(di, 0, flags);
 	if (!gpth)
 	    /*
 	     * this read might fail if bios reports different disk size (different vm/pc)
 	     * not much we can do here to avoid it
 	     */
-	    gpth = try_gpt_hdr(di, 1);
+	    gpth = try_gpt_hdr(di, 1, flags);
 	if (!gpth)
 	    goto out;
     }
@@ -682,11 +687,6 @@ struct part_iter *pi_begin(const struct disk_info *di, int flags)
 	dprintf("Looks like a GPT v1.0 disk.\n");
 	disk_gpt_header_dump(gpth);
 #endif
-	if (notsane_gpt_hdr(di, gpth, flags)) {
-	    error("GPT header values are corrupted.");
-	    goto out;
-	}
-
 	gptl = try_gpt_list(di, gpth, 0);
 	if (!gptl)
 	    gptl = try_gpt_list(di, gpth, 1);