From f0f0cfdc3a024e21161714f2e05f0df3b84d42ad Mon Sep 17 00:00:00 2001
From: Louis Rannou <lrannou@baylibre.com>
Date: Fri, 3 Feb 2023 09:07:54 +0200
Subject: [PATCH] mtd: spi-nor: Fix shift-out-of-bounds in spi_nor_set_erase_type
Git-commit: f0f0cfdc3a024e21161714f2e05f0df3b84d42ad
Patch-mainline: v6.3-rc1
References: git-fixes

spi_nor_set_erase_type() was used either to set or to mask out an erase
type. When we used it to mask out an erase type a shift-out-of-bounds
was hit:
Ubsan: shift-out-of-bounds in drivers/mtd/spi-nor/core.c:2237:24
shift exponent 4294967295 is too large for 32-bit type 'int'

The setting of the size_{shift, mask} and of the opcode are unnecessary
when the erase size is zero, as throughout the code just the erase size
is considered to determine whether an erase type is supported or not.
Setting the opcode to 0xFF was wrong too as nobody guarantees that 0xFF
is an unused opcode. Thus when masking out an erase type, just set the
erase size to zero. This will fix the shift-out-of-bounds.

Fixes: 5390a8df769e ("mtd: spi-nor: add support to non-uniform SFDP SPI NOR flash memories")
Cc: stable@vger.kernel.org
Reported-by: Alexander Stein <Alexander.Stein@tq-group.com>
Signed-off-by: Louis Rannou <lrannou@baylibre.com>
Tested-by: Alexander Stein <Alexander.Stein@tq-group.com>
Link: https://lore.kernel.org/r/20230203070754.50677-1-tudor.ambarus@linaro.org
[ta: refine changes, new commit message, fix compilation error]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mtd/spi-nor/core.c |    9 +++++++++
 drivers/mtd/spi-nor/core.h |    1 +
 drivers/mtd/spi-nor/sfdp.c |    4 ++--
 3 files changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2248,6 +2248,15 @@ void spi_nor_set_erase_type(struct spi_n
 }
 
 /**
+ * spi_nor_mask_erase_type() - mask out a SPI NOR erase type
+ * @erase:	pointer to a structure that describes a SPI NOR erase type
+ */
+void spi_nor_mask_erase_type(struct spi_nor_erase_type *erase)
+{
+	erase->size = 0;
+}
+
+/**
  * spi_nor_init_uniform_erase_map() - Initialize uniform erase map
  * @map:		the erase map of the SPI NOR
  * @erase_mask:		bitmask encoding erase types that can erase the entire
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -538,6 +538,7 @@ void spi_nor_set_pp_settings(struct spi_
 
 void spi_nor_set_erase_type(struct spi_nor_erase_type *erase, u32 size,
 			    u8 opcode);
+void spi_nor_mask_erase_type(struct spi_nor_erase_type *erase);
 struct spi_nor_erase_region *
 spi_nor_region_next(struct spi_nor_erase_region *region);
 void spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -874,7 +874,7 @@ static int spi_nor_init_non_uniform_eras
 	 */
 	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++)
 		if (!(regions_erase_type & BIT(erase[i].idx)))
-			spi_nor_set_erase_type(&erase[i], 0, 0xFF);
+			spi_nor_mask_erase_type(&erase[i]);
 
 	return 0;
 }
@@ -1088,7 +1088,7 @@ static int spi_nor_parse_4bait(struct sp
 			erase_type[i].opcode = (dwords[1] >>
 						erase_type[i].idx * 8) & 0xFF;
 		else
-			spi_nor_set_erase_type(&erase_type[i], 0u, 0xFF);
+			spi_nor_mask_erase_type(&erase_type[i]);
 	}
 
 	/*