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From: Bastien Nocera <hadess@hadess.net>
To: linux-bluetooth@vger.kernel.org
Cc: Bastien Nocera <hadess@hadess.net>
Subject: [BlueZ 5/9] shared/mainloop: Fix integer overflow
Date: Thu, 30 May 2024 16:57:59 +0200
Message-ID: <20240530150057.444585-6-hadess@hadess.net>
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signalfd_siginfo uses a u32 for the signal number, but siginfo_t uses a
signed integer for it, so an (unlikely) big value for the signal number
could result in a negative value being passed to the callbacks. Catch
that and bail early.

Error: INTEGER_OVERFLOW (CWE-190): [#def44] [important]
bluez-5.76/src/shared/mainloop-notify.c:132:2: tainted_data_argument: The value "si" is considered tainted.
bluez-5.76/src/shared/mainloop-notify.c:137:3: tainted_data_argument: "si.ssi_signo" is considered tainted.
bluez-5.76/src/shared/mainloop-notify.c:137:3: underflow: The cast of "si.ssi_signo" to a signed type could result in a negative number.
135|
136|	if (data && data->func)
137|->		data->func(si.ssi_signo, data->user_data);
138|
139|	return true;
---
 src/shared/mainloop-notify.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/shared/mainloop-notify.c b/src/shared/mainloop-notify.c
index 33be3cf8d78e..11989512e013 100644
--- a/src/shared/mainloop-notify.c
+++ b/src/shared/mainloop-notify.c
@@ -15,6 +15,7 @@
 #define _GNU_SOURCE
 #include <stdio.h>
 #include <errno.h>
+#include <limits.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <stddef.h>
@@ -130,7 +131,7 @@ static bool signal_read(struct io *io, void *user_data)
 	fd = io_get_fd(io);
 
 	result = read(fd, &si, sizeof(si));
-	if (result != sizeof(si))
+	if (result != sizeof(si) || si.ssi_signo > INT_MAX)
 		return false;
 
 	if (data && data->func)
-- 
2.45.1