From 2ff46e6fea6254ac8fa97aeb9c14e51436ab95f6 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Wed, 2 Sep 2015 16:34:35 -0700 Subject: [PATCH] mtd: spi-nor: fix NULL dereference when no match found in spi_nor_ids[] MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Commit 06bb6f5a69df ("mtd: spi-nor: stop (ab)using struct spi_device_id") converted an array into a pointer, which means that we should be checking if the pointer goes anywhere, not whether the C string is empty. To do the latter means we dereference a NULL pointer when we reach the terminating entry, for which 'name' is now NULL instead of an array { 0, 0, ... }. Sample crash: [ 1.101371] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 1.109457] pgd = c0004000 [ 1.112157] [00000000] *pgd=00000000 [ 1.115736] Internal error: Oops: 5 [#1] SMP ARM [ 1.120345] Modules linked in: [ 1.123405] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 4.2.0-next-20150902+ #61 [ 1.130611] Hardware name: Rockchip (Device Tree) [ 1.135306] task: ee0b8d40 ti: ee0ba000 task.ti: ee0ba000 [ 1.140697] PC is at spi_nor_scan+0x90/0x8c4 [ 1.144958] LR is at spi_nor_scan+0xa4/0x8c4 ... [ 1.504112] [] (spi_nor_scan) from [] (m25p_probe+0xc8/0x11c) [ 1.511583] [] (m25p_probe) from [] (spi_drv_probe+0x60/0x7c) [ 1.519055] [] (spi_drv_probe) from [] (driver_probe_device+0x1a0/0x444) [ 1.527478] [] (driver_probe_device) from [] (__device_attach_driver+0x94/0xa0) [ 1.536507] [] (__device_attach_driver) from [] (bus_for_each_drv+0x94/0xa4) [ 1.545277] [] (bus_for_each_drv) from [] (__device_attach+0xa4/0x144) [ 1.553526] [] (__device_attach) from [] (device_initial_probe+0x1c/0x20) [ 1.562035] [] (device_initial_probe) from [] (bus_probe_device+0x38/0x94) [ 1.570631] [] (bus_probe_device) from [] (device_add+0x430/0x558) [ 1.578534] [] (device_add) from [] (spi_add_device+0xe4/0x174) [ 1.586178] [] (spi_add_device) from [] (spi_register_master+0x698/0x7d4) [ 1.594688] [] (spi_register_master) from [] (devm_spi_register_master+0x40/0x7c) [ 1.603892] [] (devm_spi_register_master) from [] (rockchip_spi_probe+0x360/0x3f4) [ 1.613182] [] (rockchip_spi_probe) from [] (platform_drv_probe+0x58/0xa8) [ 1.621779] [] (platform_drv_probe) from [] (driver_probe_device+0x1a0/0x444) [ 1.630635] [] (driver_probe_device) from [] (__driver_attach+0x80/0xa4) [ 1.639058] [] (__driver_attach) from [] (bus_for_each_dev+0x98/0xac) [ 1.647221] [] (bus_for_each_dev) from [] (driver_attach+0x28/0x30) [ 1.655210] [] (driver_attach) from [] (bus_add_driver+0x128/0x250) [ 1.663200] [] (bus_add_driver) from [] (driver_register+0xac/0xf0) [ 1.671191] [] (driver_register) from [] (__platform_driver_register+0x58/0x6c) [ 1.680221] [] (__platform_driver_register) from [] (rockchip_spi_driver_init+0x18/0x20) [ 1.690033] [] (rockchip_spi_driver_init) from [] (do_one_initcall+0x124/0x1dc) [ 1.699063] [] (do_one_initcall) from [] (kernel_init_freeable+0x218/0x2ec) [ 1.707748] [] (kernel_init_freeable) from [] (kernel_init+0x1c/0xf4) [ 1.715912] [] (kernel_init) from [] (ret_from_fork+0x14/0x24) [ 1.723460] Code: e3510000 159f67c0 0a00000c e5961000 (e5d13000) [ 1.729564] ---[ end trace 95baa6b3b861ce25 ]--- Fixes: 06bb6f5a69df ("mtd: spi-nor: stop (ab)using struct spi_device_id") Signed-off-by: Brian Norris Cc: Rafał Miłecki --- drivers/mtd/spi-nor/spi-nor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index 25372f9..f59aedf 100644 --- a/drivers/mtd/spi-nor/spi-nor.c +++ b/drivers/mtd/spi-nor/spi-nor.c @@ -1218,7 +1218,7 @@ static const struct flash_info *spi_nor_match_id(const char *name) { const struct flash_info *id = spi_nor_ids; - while (id->name[0]) { + while (id->name) { if (!strcmp(name, id->name)) return id; id++; -- 2.7.4