From: Boris Brezillon boris.brezillon@free-electrons.com
Unlike what's done in mtd_read/write(), there are no checks to make sure the parameters passed to mtd_read/write_oob() are consistent, which forces implementers of ->_read/write_oob() to do it, which in turn leads to code duplication and possibly errors in the logic.
Do general sanity checks, like ops fields consistency and range checking.
Signed-off-by: Boris Brezillon boris.brezillon@free-electrons.com Cc: Peter Pan peterpandong@micron.com Signed-off-by: Richard Weinberger richard@nod.at [Miquel: squashed the fix about the chip's size check] Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com --- drivers/mtd/mtdcore.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index c22ca20368..ba170f212e 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -1011,12 +1011,50 @@ int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, } EXPORT_SYMBOL_GPL(mtd_panic_write);
+static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs, + struct mtd_oob_ops *ops) +{ + /* + * Some users are setting ->datbuf or ->oobbuf to NULL, but are leaving + * ->len or ->ooblen uninitialized. Force ->len and ->ooblen to 0 in + * this case. + */ + if (!ops->datbuf) + ops->len = 0; + + if (!ops->oobbuf) + ops->ooblen = 0; + + if (offs < 0 || offs + ops->len > mtd->size) + return -EINVAL; + + if (ops->ooblen) { + u64 maxooblen; + + if (ops->ooboffs >= mtd_oobavail(mtd, ops)) + return -EINVAL; + + maxooblen = ((mtd_div_by_ws(mtd->size, mtd) - + mtd_div_by_ws(offs, mtd)) * + mtd_oobavail(mtd, ops)) - ops->ooboffs; + if (ops->ooblen > maxooblen) + return -EINVAL; + } + + return 0; +} + int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops) { int ret_code; ops->retlen = ops->oobretlen = 0; if (!mtd->_read_oob) return -EOPNOTSUPP; + + ret_code = mtd_check_oob_ops(mtd, from, ops); + if (ret_code) + return ret_code; + /* * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics * similar to mtd->_read(), returning a non-negative integer @@ -1035,11 +1073,18 @@ EXPORT_SYMBOL_GPL(mtd_read_oob); int mtd_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops) { + int ret; + ops->retlen = ops->oobretlen = 0; if (!mtd->_write_oob) return -EOPNOTSUPP; if (!(mtd->flags & MTD_WRITEABLE)) return -EROFS; + + ret = mtd_check_oob_ops(mtd, to, ops); + if (ret) + return ret; + return mtd->_write_oob(mtd, to, ops); } EXPORT_SYMBOL_GPL(mtd_write_oob);