From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pa0-x233.google.com ([2607:f8b0:400e:c03::233]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZhKSK-0008S8-Gm for linux-mtd@lists.infradead.org; Wed, 30 Sep 2015 16:42:13 +0000 Received: by pacex6 with SMTP id ex6so45575898pac.0 for ; Wed, 30 Sep 2015 09:41:52 -0700 (PDT) From: Sudip Mukherjee To: David Woodhouse , Brian Norris Cc: linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Sudip Mukherjee Subject: [PATCH] mtd: mtdram: check offs and len in mtdram->erase Date: Wed, 30 Sep 2015 22:11:43 +0530 Message-Id: <1443631303-22057-1-git-send-email-sudipm.mukherjee@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , We should prevent user to erasing mtd device with an unaligned offset or length. Signed-off-by: Sudip Mukherjee --- I am not sure if I should add the Signed-off-by of Dongsheng Yang . He is the original author and he should get the credit for that. drivers/mtd/devices/mtdram.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/mtd/devices/mtdram.c b/drivers/mtd/devices/mtdram.c index 8e28508..21b6a05 100644 --- a/drivers/mtd/devices/mtdram.c +++ b/drivers/mtd/devices/mtdram.c @@ -32,8 +32,35 @@ MODULE_PARM_DESC(erase_size, "Device erase block size in KiB"); // We could store these in the mtd structure, but we only support 1 device.. static struct mtd_info *mtd_info; +static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len) +{ + int ret = 0; + uint64_t temp_len, rem; + + /* Start address must align on block boundary */ + temp_len = ofs; + rem = do_div(temp_len, mtd->erasesize); + if (rem) { + pr_debug("%s: unaligned address\n", __func__); + ret = -EINVAL; + } + + /* Length must align on block boundary */ + temp_len = len; + rem = do_div(temp_len, mtd->erasesize); + + if (rem) { + pr_debug("%s: length not block aligned\n", __func__); + ret = -EINVAL; + } + + return ret; +} + static int ram_erase(struct mtd_info *mtd, struct erase_info *instr) { + if (check_offs_len(mtd, instr->addr, instr->len)) + return -EINVAL; memset((char *)mtd->priv + instr->addr, 0xff, instr->len); instr->state = MTD_ERASE_DONE; mtd_erase_callback(instr); -- 1.9.1