Author: delphij
Date: Thu Oct 1 18:58:06 2020
New Revision: 366338
URL: https://svnweb.freebsd.org/changeset/base/366338
Log:
MFS r366305: MFC r366064, r366065, r366215
sbin/fsck_msdosfs: Fix an integer overflow on 32-bit platforms
Approved by: re (gjb)
Modified:
releng/12.2/sbin/fsck_msdosfs/dir.c
Directory Properties:
releng/12.2/ (props changed)
Modified: releng/12.2/sbin/fsck_msdosfs/dir.c
==============================================================================
--- releng/12.2/sbin/fsck_msdosfs/dir.c Thu Oct 1 18:56:44 2020
(r366337)
+++ releng/12.2/sbin/fsck_msdosfs/dir.c Thu Oct 1 18:58:06 2020
(r366338)
@@ -388,7 +388,8 @@ static int
checksize(struct fat_descriptor *fat, u_char *p, struct dosDirEntry *dir)
{
int ret = FSOK;
- size_t physicalSize;
+ size_t chainsize;
+ u_int64_t physicalSize;
struct bootblock *boot;
boot = fat_get_boot(fat);
@@ -401,9 +402,9 @@ checksize(struct fat_descriptor *fat, u_char *p, struc
} else {
if (!fat_is_valid_cl(fat, dir->head))
return FSERROR;
- ret = checkchain(fat, dir->head, &physicalSize);
+ ret = checkchain(fat, dir->head, &chainsize);
/*
- * Upon return, physicalSize would hold the chain length
+ * Upon return, chainsize would hold the chain length
* that checkchain() was able to validate, but if the user
* refused the proposed repair, it would be unsafe to
* proceed with directory entry fix, so bail out in that
@@ -412,11 +413,17 @@ checksize(struct fat_descriptor *fat, u_char *p, struc
if (ret == FSERROR) {
return (FSERROR);
}
- physicalSize *= boot->ClusterSize;
+ /*
+ * The maximum file size on FAT32 is 4GiB - 1, which
+ * will occupy a cluster chain of exactly 4GiB in
+ * size. On 32-bit platforms, since size_t is 32-bit,
+ * it would wrap back to 0.
+ */
+ physicalSize = (u_int64_t)chainsize * boot->ClusterSize;
}
if (physicalSize < dir->size) {
- pwarn("size of %s is %u, should at most be %zu\n",
- fullpath(dir), dir->size, physicalSize);
+ pwarn("size of %s is %u, should at most be %ju\n",
+ fullpath(dir), dir->size, (uintmax_t)physicalSize);
if (ask(1, "Truncate")) {
dir->size = physicalSize;
p[28] = (u_char)physicalSize;
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