From: Jason Baron Date: Fri, 23 Mar 2012 22:02:51 +0000 (-0700) Subject: coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP X-Git-Tag: MMI-PSA29.97-13-9~17191^2~6 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=accb61fe7bb0f5c2a4102239e4981650f9048519;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP Since we no longer need the VM_ALWAYSDUMP flag, let's use the freed bit for 'VM_NODUMP' flag. The idea is is to add a new madvise() flag: MADV_DONTDUMP, which can be set by applications to specifically request memory regions which should not dump core. The specific application I have in mind is qemu: we can add a flag there that wouldn't dump all of guest memory when qemu dumps core. This flag might also be useful for security sensitive apps that want to absolutely make sure that parts of memory are not dumped. To clear the flag use: MADV_DODUMP. [akpm@linux-foundation.org: s/MADV_NODUMP/MADV_DONTDUMP/, s/MADV_CLEAR_NODUMP/MADV_DODUMP/, per Roland] [akpm@linux-foundation.org: fix up the architectures which broke] Signed-off-by: Jason Baron Acked-by: Roland McGrath Cc: Chris Metcalf Cc: Avi Kivity Cc: Ralf Baechle Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: "James E.J. Bottomley" Cc: Helge Deller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/alpha/include/asm/mman.h b/arch/alpha/include/asm/mman.h index 72db984f8781..cbeb3616a28e 100644 --- a/arch/alpha/include/asm/mman.h +++ b/arch/alpha/include/asm/mman.h @@ -56,6 +56,10 @@ #define MADV_HUGEPAGE 14 /* Worth backing with hugepages */ #define MADV_NOHUGEPAGE 15 /* Not worth backing with hugepages */ +#define MADV_DONTDUMP 16 /* Explicity exclude from the core dump, + overrides the coredump filter bits */ +#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/arch/mips/include/asm/mman.h b/arch/mips/include/asm/mman.h index 785b4ea4ec3f..46d3da0d4b92 100644 --- a/arch/mips/include/asm/mman.h +++ b/arch/mips/include/asm/mman.h @@ -80,6 +80,10 @@ #define MADV_HUGEPAGE 14 /* Worth backing with hugepages */ #define MADV_NOHUGEPAGE 15 /* Not worth backing with hugepages */ +#define MADV_DONTDUMP 16 /* Explicity exclude from the core dump, + overrides the coredump filter bits */ +#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h index f5b7bf5fba68..12219ebce869 100644 --- a/arch/parisc/include/asm/mman.h +++ b/arch/parisc/include/asm/mman.h @@ -62,6 +62,10 @@ #define MADV_HUGEPAGE 67 /* Worth backing with hugepages */ #define MADV_NOHUGEPAGE 68 /* Not worth backing with hugepages */ +#define MADV_DONTDUMP 69 /* Explicity exclude from the core dump, + overrides the coredump filter bits */ +#define MADV_DODUMP 70 /* Clear the MADV_NODUMP flag */ + /* compatibility flags */ #define MAP_FILE 0 #define MAP_VARIABLE 0 diff --git a/arch/xtensa/include/asm/mman.h b/arch/xtensa/include/asm/mman.h index 30789010733d..25bc6c1309c3 100644 --- a/arch/xtensa/include/asm/mman.h +++ b/arch/xtensa/include/asm/mman.h @@ -86,6 +86,10 @@ #define MADV_HUGEPAGE 14 /* Worth backing with hugepages */ #define MADV_NOHUGEPAGE 15 /* Not worth backing with hugepages */ +#define MADV_DONTDUMP 16 /* Explicity exclude from the core dump, + overrides the coredump filter bits */ +#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index b64be5b5ac21..504b6eee50a9 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1127,6 +1127,9 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, if (always_dump_vma(vma)) goto whole; + if (vma->vm_flags & VM_NODUMP) + return 0; + /* Hugetlb memory check */ if (vma->vm_flags & VM_HUGETLB) { if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) diff --git a/include/asm-generic/mman-common.h b/include/asm-generic/mman-common.h index 787abbb6d867..d030d2c2647a 100644 --- a/include/asm-generic/mman-common.h +++ b/include/asm-generic/mman-common.h @@ -48,6 +48,10 @@ #define MADV_HUGEPAGE 14 /* Worth backing with hugepages */ #define MADV_NOHUGEPAGE 15 /* Not worth backing with hugepages */ +#define MADV_DONTDUMP 16 /* Explicity exclude from the core dump, + overrides the coredump filter bits */ +#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/include/linux/mm.h b/include/linux/mm.h index 2de2ddba51d4..a6fabdfd34c5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -111,6 +111,7 @@ extern unsigned int kobjsize(const void *objp); #define VM_HUGEPAGE 0x01000000 /* MADV_HUGEPAGE marked this vma */ #endif #define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */ +#define VM_NODUMP 0x04000000 /* Do not include in the core dump */ #define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */ #define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */ diff --git a/mm/madvise.c b/mm/madvise.c index f5ab745672b7..1ccbba5b6674 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -65,6 +65,12 @@ static long madvise_behavior(struct vm_area_struct * vma, } new_flags &= ~VM_DONTCOPY; break; + case MADV_DONTDUMP: + new_flags |= VM_NODUMP; + break; + case MADV_DODUMP: + new_flags &= ~VM_NODUMP; + break; case MADV_MERGEABLE: case MADV_UNMERGEABLE: error = ksm_madvise(vma, start, end, behavior, &new_flags); @@ -293,6 +299,8 @@ madvise_behavior_valid(int behavior) case MADV_HUGEPAGE: case MADV_NOHUGEPAGE: #endif + case MADV_DONTDUMP: + case MADV_DODUMP: return 1; default: