The tag->hdr.size cannot be larger than XXX. Otherwise we can getsomething similar during boot:
Unable to handle kernel paging request at virtual address 61a05020 ... Signed-off-by: Tony Lindgren <[email protected]> --- arch/arm/include/asm/setup.h | 12 +++++++++--- arch/arm/kernel/atags.c | 2 +- arch/arm/kernel/compat.c | 2 +- arch/arm/kernel/setup.c | 4 ++-- arch/arm/mach-orion5x/common.c | 2 +- 5 files changed, 14 insertions(+), 8 deletions(-) diff --git a/arch/arm/include/asm/setup.h b/arch/arm/include/asm/setup.h index 5ccce0a..3ca36bb 100644 --- a/arch/arm/include/asm/setup.h +++ b/arch/arm/include/asm/setup.h @@ -21,6 +21,11 @@ /* The list ends with an ATAG_NONE node. */ #define ATAG_NONE 0x00000000 +/* Some sanity checks are needed */ +#define ATAG_MAX_SZ PAGE_SIZE +#define atag_valid(tag) \ + ((tag)->hdr.size && ((tag)->hdr.size <= ATAG_MAX_SZ)) + struct tag_header { __u32 size; __u32 tag; @@ -173,9 +178,10 @@ struct tagtable { int (*parse)(const struct tag *); }; -#define tag_member_present(tag,member) \ - ((unsigned long)(&((struct tag *)0L)->member + 1) \ - <= (tag)->hdr.size * 4) +#define tag_member_present(tag,member) \ + (atag_valid(tag) && \ + (((unsigned long)(&((struct tag *)0L)->member + 1) \ + <= (tag)->hdr.size * 4)) #define tag_next(t) ((struct tag *)((__u32 *)(t) + (t)->hdr.size)) #define tag_size(type) ((sizeof(struct tag_header) + sizeof(struct type)) >> 2) diff --git a/arch/arm/kernel/atags.c b/arch/arm/kernel/atags.c index 42a1a14..14d0993 100644 --- a/arch/arm/kernel/atags.c +++ b/arch/arm/kernel/atags.c @@ -51,7 +51,7 @@ static int __init init_atags_procfs(void) return -EINVAL; } - for (; tag->hdr.size; tag = tag_next(tag)) + for (; atag_valid(tag); tag = tag_next(tag)) ; /* include the terminating ATAG_NONE */ diff --git a/arch/arm/kernel/compat.c b/arch/arm/kernel/compat.c index 0a13854..3e63ee1 100644 --- a/arch/arm/kernel/compat.c +++ b/arch/arm/kernel/compat.c @@ -220,7 +220,7 @@ void __init convert_to_tag_list(struct tag *tags) void __init squash_mem_tags(struct tag *tag) { - for (; tag->hdr.size; tag = tag_next(tag)) + for (; atag_valid(tag); tag = tag_next(tag)) if (tag->hdr.tag == ATAG_MEM) tag->hdr.tag = ATAG_NONE; } diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index c6c57b6..53d7181 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -556,7 +556,7 @@ request_standard_resources(struct meminfo *mi, struct machine_desc *mdesc) */ static int __init parse_tag_core(const struct tag *tag) { - if (tag->hdr.size > 2) { + if ((atag_valid(tag) && (tag->hdr.size > 2))) { if ((tag->u.core.flags & 1) == 0) root_mountflags &= ~MS_RDONLY; ROOT_DEV = old_decode_dev(tag->u.core.rootdev); @@ -660,7 +660,7 @@ static int __init parse_tag(const struct tag *tag) */ static void __init parse_tags(const struct tag *t) { - for (; t->hdr.size; t = tag_next(t)) + for (; atag_valid(t); t = tag_next(t)) if (!parse_tag(t)) printk(KERN_WARNING "Ignoring unrecognised tag 0x%08x\n", diff --git a/arch/arm/mach-orion5x/common.c b/arch/arm/mach-orion5x/common.c index f87fa12..8afee34 100644 --- a/arch/arm/mach-orion5x/common.c +++ b/arch/arm/mach-orion5x/common.c @@ -717,7 +717,7 @@ void __init orion5x_init(void) void __init tag_fixup_mem32(struct machine_desc *mdesc, struct tag *t, char **from, struct meminfo *meminfo) { - for (; t->hdr.size; t = tag_next(t)) + for (; atag_valid(t); t = tag_next(t)) if (t->hdr.tag == ATAG_MEM && (!t->u.mem.size || t->u.mem.size & ~PAGE_MASK || t->u.mem.start & ~PAGE_MASK)) { -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
