Commit 10970e1b authored by Borislav Petkov's avatar Borislav Petkov

x86/a.out: Clear the dump structure initially

dump_thread32() in aout_core_dump() does not clear the user32 structure
allocated on the stack as the first thing on function entry.

As a result, the dump.u_comm, dump.u_ar0 and dump.signal which get
assigned before the clearing, get overwritten.

Rename that function to fill_dump() to make it clear what it does and
call it first thing.

This was caught while staring at a patch by Derek Robson
<robsonde@gmail.com>.
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Derek Robson <robsonde@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Matz <matz@suse.de>
Cc: x86@kernel.org
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190202005512.3144-1-robsonde@gmail.com
parent 20e55bc1
...@@ -51,7 +51,7 @@ static unsigned long get_dr(int n) ...@@ -51,7 +51,7 @@ static unsigned long get_dr(int n)
/* /*
* fill in the user structure for a core dump.. * fill in the user structure for a core dump..
*/ */
static void dump_thread32(struct pt_regs *regs, struct user32 *dump) static void fill_dump(struct pt_regs *regs, struct user32 *dump)
{ {
u32 fs, gs; u32 fs, gs;
memset(dump, 0, sizeof(*dump)); memset(dump, 0, sizeof(*dump));
...@@ -157,10 +157,12 @@ static int aout_core_dump(struct coredump_params *cprm) ...@@ -157,10 +157,12 @@ static int aout_core_dump(struct coredump_params *cprm)
fs = get_fs(); fs = get_fs();
set_fs(KERNEL_DS); set_fs(KERNEL_DS);
has_dumped = 1; has_dumped = 1;
fill_dump(cprm->regs, &dump);
strncpy(dump.u_comm, current->comm, sizeof(current->comm)); strncpy(dump.u_comm, current->comm, sizeof(current->comm));
dump.u_ar0 = offsetof(struct user32, regs); dump.u_ar0 = offsetof(struct user32, regs);
dump.signal = cprm->siginfo->si_signo; dump.signal = cprm->siginfo->si_signo;
dump_thread32(cprm->regs, &dump);
/* /*
* If the size of the dump file exceeds the rlimit, then see * If the size of the dump file exceeds the rlimit, then see
......
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