From 674470d97958a0ec72f72caf7f6451da40159cc7 Mon Sep 17 00:00:00 2001 From: Joonyoung Shim Date: Wed, 11 Sep 2013 14:21:43 -0700 Subject: lib/genalloc.c: fix overflow of ending address of memory chunk In struct gen_pool_chunk, end_addr means the end address of memory chunk (inclusive), but in the implementation it is treated as address + size of memory chunk (exclusive), so it points to the address plus one instead of correct ending address. The ending address of memory chunk plus one will cause overflow on the memory chunk including the last address of memory map, e.g. when starting address is 0xFFF00000 and size is 0x100000 on 32bit machine, ending address will be 0x100000000. Use correct ending address like starting address + size - 1. [akpm@linux-foundation.org: add comment to struct gen_pool_chunk:end_addr] Signed-off-by: Joonyoung Shim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/genalloc.h | 4 ++-- lib/genalloc.c | 19 ++++++++++++------- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h index 661d374aeb2d..f8d41cb1cbe0 100644 --- a/include/linux/genalloc.h +++ b/include/linux/genalloc.h @@ -66,8 +66,8 @@ struct gen_pool_chunk { struct list_head next_chunk; /* next chunk in pool */ atomic_t avail; phys_addr_t phys_addr; /* physical starting address of memory chunk */ - unsigned long start_addr; /* starting address of memory chunk */ - unsigned long end_addr; /* ending address of memory chunk */ + unsigned long start_addr; /* start address of memory chunk */ + unsigned long end_addr; /* end address of memory chunk (inclusive) */ unsigned long bits[0]; /* bitmap for allocating memory chunk */ }; diff --git a/lib/genalloc.c b/lib/genalloc.c index b35cfa9bc3d4..2a39bf62d8c1 100644 --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -37,6 +37,11 @@ #include #include +static inline size_t chunk_size(const struct gen_pool_chunk *chunk) +{ + return chunk->end_addr - chunk->start_addr + 1; +} + static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set) { unsigned long val, nval; @@ -188,7 +193,7 @@ int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phy chunk->phys_addr = phys; chunk->start_addr = virt; - chunk->end_addr = virt + size; + chunk->end_addr = virt + size - 1; atomic_set(&chunk->avail, size); spin_lock(&pool->lock); @@ -213,7 +218,7 @@ phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr) rcu_read_lock(); list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { - if (addr >= chunk->start_addr && addr < chunk->end_addr) { + if (addr >= chunk->start_addr && addr <= chunk->end_addr) { paddr = chunk->phys_addr + (addr - chunk->start_addr); break; } @@ -242,7 +247,7 @@ void gen_pool_destroy(struct gen_pool *pool) chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk); list_del(&chunk->next_chunk); - end_bit = (chunk->end_addr - chunk->start_addr) >> order; + end_bit = chunk_size(chunk) >> order; bit = find_next_bit(chunk->bits, end_bit, 0); BUG_ON(bit < end_bit); @@ -283,7 +288,7 @@ unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) if (size > atomic_read(&chunk->avail)) continue; - end_bit = (chunk->end_addr - chunk->start_addr) >> order; + end_bit = chunk_size(chunk) >> order; retry: start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits, pool->data); @@ -330,8 +335,8 @@ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) nbits = (size + (1UL << order) - 1) >> order; rcu_read_lock(); list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { - if (addr >= chunk->start_addr && addr < chunk->end_addr) { - BUG_ON(addr + size > chunk->end_addr); + if (addr >= chunk->start_addr && addr <= chunk->end_addr) { + BUG_ON(addr + size - 1 > chunk->end_addr); start_bit = (addr - chunk->start_addr) >> order; remain = bitmap_clear_ll(chunk->bits, start_bit, nbits); BUG_ON(remain); @@ -400,7 +405,7 @@ size_t gen_pool_size(struct gen_pool *pool) rcu_read_lock(); list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) - size += chunk->end_addr - chunk->start_addr; + size += chunk_size(chunk); rcu_read_unlock(); return size; } -- cgit v1.2.3