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Levin" , Alexey Gladkov , Eugene Syromyatnikov , Charlie Jenkins , strace-devel@lists.strace.io, linux-api@vger.kernel.org Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v2=5D_ptrace=3A_reject_out_of_rang?= =?US-ASCII?Q?e_error_values_in_PTRACE=5FSET=5FSYSCALL=5FINFO?= In-Reply-To: <20261115082540.385386-1-renzo@cs.unibo.it> References: <2D2A202C-35F8-4200-9110-B0E636216FCF@linux.dev> <20261115082540.385386-1-renzo@cs.unibo.it> Message-ID: <71963633-481A-4C74-AF99-043C0C694FB1@linux.dev> X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit On 15 November 2026 08:25:39 GMT, Renzo Davoli wrote: >With is_error set, PTRACE_SET_SYSCALL_INFO passes info.exit.rval to >syscall_set_return_value() as an "int" error without checking it: a >positive value, or on 64-bit one outside the "int" range, turns the >error into a success or is truncated. > >Reject with -ERANGE any error value outside [-MAX_ERRNO, -1]. > >Fixes: 26bb32768fe6 ("ptrace: introduce PTRACE_SET_SYSCALL_INFO request") CC:stable? Reviewed-by: Bradley Morgan >Signed-off-by: Renzo Davoli >--- >v2: shorter commit message and comment, dropped Assisted-by (Bradley Morgan) >v1: https://lore.kernel.org/lkml/20261114184842.373304-1-renzo@cs.unibo.it/ > >Tested on x86_64: rval 0, 1, 3, -4096, INT_MIN and 0x100000000 with >is_error set are now rejected with -ERANGE; -ESRCH and -4095 still work. I don't know why ai does these kinds of sections tbf. I think testing is like a basic requirement, like so basic that it wouldn't need to be added as a section > > kernel/ptrace.c | 4 ++++ > 1 file changed, 4 insertions(+) > >diff --git a/kernel/ptrace.c b/kernel/ptrace.c >index 3f2fe68ccb14..1ffacfcef8d4 100644 >--- a/kernel/ptrace.c >+++ b/kernel/ptrace.c >@@ -1111,6 +1111,10 @@ ptrace_set_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, > if (rval != info->exit.rval) > return -ERANGE; > >+ /* An error must be a negative errno value. */ >+ if (info->exit.is_error && (rval < -MAX_ERRNO || rval >= 0)) >+ return -ERANGE; >+ please consider Renzos comment and add a test case. > if (info->exit.is_error) > syscall_set_return_value(child, regs, rval, 0); > else > >base-commit: 7e1392a42ea288d70a266f6553fe06f57f8647ea > --- Thanks!