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mtd: nftl: Remove VLA usage 

On the quest to remove all stack VLAs from the kernel[1] this changes
the check_free_sectors() routine to use a kmalloc()ed buffer instead
of a large VLA stack buffer.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
This commit is contained in:
Kees Cook 2018-04-29 08:00:53 -07:00 committed by Boris Brezillon
parent 7cc9aa669a
commit 27ab41e2c1
2 changed files with 32 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/mtd/inftlmount.c
View File

@ -334,28 +334,37 @@ static int memcmpb(void *a, int c, int n)
static int check_free_sectors(struct INFTLrecord *inftl, unsigned int address,
int len, int check_oob)
{
u8 buf[SECTORSIZE + inftl->mbd.mtd->oobsize];
struct mtd_info *mtd = inftl->mbd.mtd;
size_t retlen;
int i;
int i, ret;
u8 *buf;
buf = kmalloc(SECTORSIZE + mtd->oobsize, GFP_KERNEL);
if (!buf)
return -1;
ret = -1;
for (i = 0; i < len; i += SECTORSIZE) {
if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
return -1;
goto out;
if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
return -1;
goto out;
if (check_oob) {
if(inftl_read_oob(mtd, address, mtd->oobsize,
&retlen, &buf[SECTORSIZE]) < 0)
return -1;
goto out;
if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
return -1;
goto out;
}
address += SECTORSIZE;
}
return 0;
ret = 0;
out:
kfree(buf);
return ret;
}
/*

23
drivers/mtd/nftlmount.c
View File

@ -272,28 +272,37 @@ static int memcmpb(void *a, int c, int n)
static int check_free_sectors(struct NFTLrecord *nftl, unsigned int address, int len,
int check_oob)
{
u8 buf[SECTORSIZE + nftl->mbd.mtd->oobsize];
struct mtd_info *mtd = nftl->mbd.mtd;
size_t retlen;
int i;
int i, ret;
u8 *buf;
buf = kmalloc(SECTORSIZE + mtd->oobsize, GFP_KERNEL);
if (!buf)
return -1;
ret = -1;
for (i = 0; i < len; i += SECTORSIZE) {
if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
return -1;
goto out;
if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
return -1;
goto out;
if (check_oob) {
if(nftl_read_oob(mtd, address, mtd->oobsize,
&retlen, &buf[SECTORSIZE]) < 0)
return -1;
goto out;
if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
return -1;
goto out;
}
address += SECTORSIZE;
}
return 0;
ret = 0;
out:
kfree(buf);
return ret;
}
/* NFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase Unit and