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authorAl Viro <viro@ftp.linux.org.uk>2006-02-26 08:34:10 -0600
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-26 09:09:49 -0800
commit489708007785389941a89fa06aedc5ec53303c96 (patch)
tree425e0dda8d5fec842ffdd3b2cdadfeaf60f5a668
parenta0124d780d06db711e8a92135d774940588a27da (diff)
downloadlinux-linaro-489708007785389941a89fa06aedc5ec53303c96.tar.gz
[PATCH] sd: fix memory corruption with broken mode page headers
There's a problem in sd where we blindly believe the length of the headers and block descriptors. Some devices return insane values for these and cause our length to end up greater than the actual buffer size, so check to make sure. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Also removed the buffer size magic number (512) and added DPOFUA of zero to the defaults Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/scsi/sd.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 930db398d10..9d9872347f5 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -89,6 +89,11 @@
#define SD_MAX_RETRIES 5
#define SD_PASSTHROUGH_RETRIES 1
+/*
+ * Size of the initial data buffer for mode and read capacity data
+ */
+#define SD_BUF_SIZE 512
+
static void scsi_disk_release(struct kref *kref);
struct scsi_disk {
@@ -1239,7 +1244,7 @@ sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
/*
* read write protect setting, if possible - called only in sd_revalidate_disk()
- * called with buffer of length 512
+ * called with buffer of length SD_BUF_SIZE
*/
static void
sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
@@ -1297,7 +1302,7 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
/*
* sd_read_cache_type - called only from sd_revalidate_disk()
- * called with buffer of length 512
+ * called with buffer of length SD_BUF_SIZE
*/
static void
sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
@@ -1342,6 +1347,8 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
/* Take headers and block descriptors into account */
len += data.header_length + data.block_descriptor_length;
+ if (len > SD_BUF_SIZE)
+ goto bad_sense;
/* Get the data */
res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
@@ -1354,6 +1361,12 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
int ct = 0;
int offset = data.header_length + data.block_descriptor_length;
+ if (offset >= SD_BUF_SIZE - 2) {
+ printk(KERN_ERR "%s: malformed MODE SENSE response",
+ diskname);
+ goto defaults;
+ }
+
if ((buffer[offset] & 0x3f) != modepage) {
printk(KERN_ERR "%s: got wrong page\n", diskname);
goto defaults;
@@ -1398,6 +1411,7 @@ defaults:
diskname);
sdkp->WCE = 0;
sdkp->RCD = 0;
+ sdkp->DPOFUA = 0;
}
/**
@@ -1421,7 +1435,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
if (!scsi_device_online(sdp))
goto out;
- buffer = kmalloc(512, GFP_KERNEL | __GFP_DMA);
+ buffer = kmalloc(SD_BUF_SIZE, GFP_KERNEL | __GFP_DMA);
if (!buffer) {
printk(KERN_WARNING "(sd_revalidate_disk:) Memory allocation "
"failure.\n");