lkml.org 
[lkml]   [2018]   [Jun]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 01/14] ubi: fastmap: Read PEB numbers more carefully
Date
PEB numbers can be used as indices, make sure that they
are within bounds.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
drivers/mtd/ubi/fastmap.c | 71 ++++++++++++++++++++++++++++++++++++++---------
1 file changed, 58 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 462526a10537..768fa8a76867 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -101,6 +101,29 @@ size_t ubi_calc_fm_size(struct ubi_device *ubi)
return roundup(size, ubi->leb_size);
}

+static bool read_pnum(struct ubi_device *ubi, struct ubi_attach_info *ai,
+ __be32 pnum, int *out_pnum)
+{
+ int ret = true;
+ int max_pnum = ubi->peb_count;
+
+ pnum = be32_to_cpu(pnum);
+ if (pnum == UBI_UNKNOWN) {
+ *out_pnum = pnum;
+ goto out;
+ }
+
+ if (pnum < 0 || pnum >= max_pnum) {
+ ubi_err(ubi, "fastmap references PEB out of range: %i", pnum);
+ ret = false;
+ goto out;
+ } else {
+ *out_pnum = pnum;
+ }
+
+out:
+ return ret;
+}

/**
* new_fm_vhdr - allocate a new volume header for fastmap usage.
@@ -438,7 +461,10 @@ static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
int scrub = 0;
int image_seq;

- pnum = be32_to_cpu(pebs[i]);
+ if (!read_pnum(ubi, ai, pebs[i], &pnum)) {
+ ret = UBI_BAD_FASTMAP;
+ goto out;
+ }

if (ubi_io_is_bad(ubi, pnum)) {
ubi_err(ubi, "bad PEB in fastmap pool!");
@@ -565,7 +591,7 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
struct ubi_fm_ec *fmec;
struct ubi_fm_volhdr *fmvhdr;
struct ubi_fm_eba *fm_eba;
- int ret, i, j, pool_size, wl_pool_size;
+ int ret, i, j, pool_size, wl_pool_size, pnum;
size_t fm_pos = 0, fm_size = ubi->fm_size;
unsigned long long max_sqnum = 0;
void *fm_raw = ubi->fm_buf;
@@ -647,8 +673,10 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
if (fm_pos >= fm_size)
goto fail_bad;

- add_aeb(ai, &ai->free, be32_to_cpu(fmec->pnum),
- be32_to_cpu(fmec->ec), 0);
+ if (!read_pnum(ubi, ai, fmec->pnum, &pnum))
+ goto fail_bad;
+
+ add_aeb(ai, &ai->free, pnum, be32_to_cpu(fmec->ec), 0);
}

/* read EC values from used list */
@@ -658,8 +686,10 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
if (fm_pos >= fm_size)
goto fail_bad;

- add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
- be32_to_cpu(fmec->ec), 0);
+ if (!read_pnum(ubi, ai, fmec->pnum, &pnum))
+ goto fail_bad;
+
+ add_aeb(ai, &used, pnum, be32_to_cpu(fmec->ec), 0);
}

/* read EC values from scrub list */
@@ -669,8 +699,10 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
if (fm_pos >= fm_size)
goto fail_bad;

- add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
- be32_to_cpu(fmec->ec), 1);
+ if (!read_pnum(ubi, ai, fmec->pnum, &pnum))
+ goto fail_bad;
+
+ add_aeb(ai, &used, pnum, be32_to_cpu(fmec->ec), 1);
}

/* read EC values from erase list */
@@ -680,8 +712,10 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
if (fm_pos >= fm_size)
goto fail_bad;

- add_aeb(ai, &ai->erase, be32_to_cpu(fmec->pnum),
- be32_to_cpu(fmec->ec), 1);
+ if (!read_pnum(ubi, ai, fmec->pnum, &pnum))
+ goto fail_bad;
+
+ add_aeb(ai, &ai->erase, pnum, be32_to_cpu(fmec->ec), 1);
}

ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
@@ -731,7 +765,8 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
}

for (j = 0; j < be32_to_cpu(fm_eba->reserved_pebs); j++) {
- int pnum = be32_to_cpu(fm_eba->pnum[j]);
+ if (!read_pnum(ubi, ai, fm_eba->pnum[j], &pnum))
+ goto fail_bad;

if (pnum < 0)
continue;
@@ -954,7 +989,10 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
for (i = 0; i < used_blocks; i++) {
int image_seq;

- pnum = be32_to_cpu(fmsb->block_loc[i]);
+ if (!read_pnum(ubi, ai, fmsb->block_loc[i], &pnum)) {
+ ret = UBI_BAD_FASTMAP;
+ goto free_hdr;
+ }

if (ubi_io_is_bad(ubi, pnum)) {
ret = UBI_BAD_FASTMAP;
@@ -1068,7 +1106,14 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
goto free_hdr;
}

- e->pnum = be32_to_cpu(fmsb2->block_loc[i]);
+ if (!read_pnum(ubi, ai, fmsb2->block_loc[i], &e->pnum)) {
+ while (i--)
+ kmem_cache_free(ubi_wl_entry_slab, fm->e[i]);
+
+ ret = -ENOMEM;
+ goto free_hdr;
+ }
+
e->ec = be32_to_cpu(fmsb2->block_ec[i]);
fm->e[i] = e;
}
--
2.13.6
\
 
 \ /
  Last update: 2018-06-13 23:26    [W:0.068 / U:11.712 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site