coredump: add a new elf note with siginfo of the signal
Existing PRSTATUS note contains only si_signo, si_code, si_errno fields
from the siginfo of the signal which caused core to be dumped.
There are tools which try to analyze crashes for possible security
implications, and they want to use, among other data, si_addr field from
the SIGSEGV.
This patch adds a new elf note, NT_SIGINFO, which contains the complete
siginfo_t of the signal which killed the process.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Amerigo Wang <amwang@redhat.com>
Cc: "Jonathan M. Foote" <jmfoote@cert.org>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 4450e82..865f9be 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -37,6 +37,10 @@
#include <asm/page.h>
#include <asm/exec.h>
+#ifndef user_siginfo_t
+#define user_siginfo_t siginfo_t
+#endif
+
static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
static int load_elf_library(struct file *);
static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
@@ -1372,6 +1376,16 @@
fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
}
+static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
+ siginfo_t *siginfo)
+{
+ mm_segment_t old_fs = get_fs();
+ set_fs(KERNEL_DS);
+ copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
+ set_fs(old_fs);
+ fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
+}
+
#ifdef CORE_DUMP_USE_REGSET
#include <linux/regset.h>
@@ -1385,7 +1399,9 @@
struct elf_note_info {
struct elf_thread_core_info *thread;
struct memelfnote psinfo;
+ struct memelfnote signote;
struct memelfnote auxv;
+ user_siginfo_t csigdata;
size_t size;
int thread_notes;
};
@@ -1559,6 +1575,9 @@
fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
info->size += notesize(&info->psinfo);
+ fill_siginfo_note(&info->signote, &info->csigdata, siginfo);
+ info->size += notesize(&info->signote);
+
fill_auxv_note(&info->auxv, current->mm);
info->size += notesize(&info->auxv);
@@ -1588,6 +1607,8 @@
if (first && !writenote(&info->psinfo, file, foffset))
return 0;
+ if (first && !writenote(&info->signote, file, foffset))
+ return 0;
if (first && !writenote(&info->auxv, file, foffset))
return 0;
@@ -1681,6 +1702,7 @@
#ifdef ELF_CORE_COPY_XFPREGS
elf_fpxregset_t *xfpu;
#endif
+ user_siginfo_t csigdata;
int thread_status_size;
int numnote;
};
@@ -1690,8 +1712,8 @@
memset(info, 0, sizeof(*info));
INIT_LIST_HEAD(&info->thread_list);
- /* Allocate space for six ELF notes */
- info->notes = kmalloc(6 * sizeof(struct memelfnote), GFP_KERNEL);
+ /* Allocate space for ELF notes */
+ info->notes = kmalloc(7 * sizeof(struct memelfnote), GFP_KERNEL);
if (!info->notes)
return 0;
info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
@@ -1763,6 +1785,7 @@
info->numnote = 2;
+ fill_siginfo_note(&info->notes[info->numnote++], &info->csigdata, siginfo);
fill_auxv_note(&info->notes[info->numnote++], current->mm);
/* Try to dump the FPU. */
diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c
index 112e45a..0fbcf63 100644
--- a/fs/compat_binfmt_elf.c
+++ b/fs/compat_binfmt_elf.c
@@ -38,6 +38,12 @@
#define elf_addr_t Elf32_Addr
/*
+ * Some data types as stored in coredump.
+ */
+#define user_siginfo_t compat_siginfo_t
+#define copy_siginfo_to_user copy_siginfo_to_user32
+
+/*
* The machine-dependent core note format types are defined in elfcore-compat.h,
* which requires asm/elf.h to define compat_elf_gregset_t et al.
*/
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 0a05051..dc62da7 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -372,6 +372,11 @@
#define NT_PRPSINFO 3
#define NT_TASKSTRUCT 4
#define NT_AUXV 6
+/*
+ * Note to userspace developers: size of NT_SIGINFO note may increase
+ * in the future to accomodate more fields, don't assume it is fixed!
+ */
+#define NT_SIGINFO 0x53494749
#define NT_PRXFPREG 0x46e62b7f /* copied from gdb5.1/include/elf/common.h */
#define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */
#define NT_PPC_SPE 0x101 /* PowerPC SPE/EVR registers */
