4.20-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov bp@suse.de
commit 10970e1b4be9c74fce8ab6e3c34a7d718f063f2c upstream.
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: Borislav 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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/ia32/ia32_aout.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/arch/x86/ia32/ia32_aout.c +++ b/arch/x86/ia32/ia32_aout.c @@ -51,7 +51,7 @@ static unsigned long get_dr(int n) /* * 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; memset(dump, 0, sizeof(*dump)); @@ -157,10 +157,12 @@ static int aout_core_dump(struct coredum fs = get_fs(); set_fs(KERNEL_DS); has_dumped = 1; + + fill_dump(cprm->regs, &dump); + strncpy(dump.u_comm, current->comm, sizeof(current->comm)); dump.u_ar0 = offsetof(struct user32, regs); dump.signal = cprm->siginfo->si_signo; - dump_thread32(cprm->regs, &dump);
/* * If the size of the dump file exceeds the rlimit, then see