From f2531f1976d98a7a4328da7f3cbf31b7c1927738 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 7 Mar 2018 12:18:33 -0800 Subject: [PATCH] pstore/ram: Do not use stack VLA for parity workspace Instead of using a stack VLA for the parity workspace, preallocate a memory region. The preallocation is done to keep from needing to perform allocations during crash dump writing, etc. This also fixes a missed release of librs on free. Signed-off-by: Kees Cook --- fs/pstore/ram_core.c | 29 ++++++++++++++++++++++------- include/linux/pstore_ram.h | 1 + 2 files changed, 23 insertions(+), 7 deletions(-) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index e11672aa4575..951a14edcf51 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -98,24 +98,23 @@ static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz, uint8_t *data, size_t len, uint8_t *ecc) { int i; - uint16_t par[prz->ecc_info.ecc_size]; /* Initialize the parity buffer */ - memset(par, 0, sizeof(par)); - encode_rs8(prz->rs_decoder, data, len, par, 0); + memset(prz->ecc_info.par, 0, + prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0])); + encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0); for (i = 0; i < prz->ecc_info.ecc_size; i++) - ecc[i] = par[i]; + ecc[i] = prz->ecc_info.par[i]; } static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz, void *data, size_t len, uint8_t *ecc) { int i; - uint16_t par[prz->ecc_info.ecc_size]; for (i = 0; i < prz->ecc_info.ecc_size; i++) - par[i] = ecc[i]; - return decode_rs8(prz->rs_decoder, data, par, len, + prz->ecc_info.par[i] = ecc[i]; + return decode_rs8(prz->rs_decoder, data, prz->ecc_info.par, len, NULL, 0, NULL, 0, NULL); } @@ -228,6 +227,15 @@ static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, return -EINVAL; } + /* allocate workspace instead of using stack VLA */ + prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size, + sizeof(*prz->ecc_info.par), + GFP_KERNEL); + if (!prz->ecc_info.par) { + pr_err("cannot allocate ECC parity workspace\n"); + return -ENOMEM; + } + prz->corrected_bytes = 0; prz->bad_blocks = 0; @@ -514,6 +522,13 @@ void persistent_ram_free(struct persistent_ram_zone *prz) } prz->vaddr = NULL; } + if (prz->rs_decoder) { + free_rs(prz->rs_decoder); + prz->rs_decoder = NULL; + } + kfree(prz->ecc_info.par); + prz->ecc_info.par = NULL; + persistent_ram_free_old(prz); kfree(prz); } diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h index 9395f06e8372..e6d226464838 100644 --- a/include/linux/pstore_ram.h +++ b/include/linux/pstore_ram.h @@ -39,6 +39,7 @@ struct persistent_ram_ecc_info { int ecc_size; int symsize; int poly; + uint16_t *par; }; struct persistent_ram_zone { -- 2.30.2