Hi all, When tracking mmaps from LSM with the following hook: static int file_mmap(struct file *file, unsigned long reqprot, unsigned long prot, unsigned long flags, unsigned long addr, unsigned long addr_only); I often get: file = NULL flags = 0x0 (MAP_FILE) prot = 0x0 (PROT_NONE) I am wondering what is the use for mmap with MAP_FILE and PROT_NONE together ? Not sure how to interpret that ? -- Christophe
Hi... On Thu, Aug 23, 2012 at 8:06 PM, Christophe Hauser <christophe.hauser@supelec.fr> wrote:
I often get: file = NULL flags = 0x0 (MAP_FILE) prot = 0x0 (PROT_NONE)
I am wondering what is the use for mmap with MAP_FILE and PROT_NONE together ? Not sure how to interpret that ?
hmm, things that cross my mind: - protecting low memory address (capturing null pointer abuse) - stack guard...to catch buffer over flow Maybe there are others.... CMIIW -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
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