Merge tag 'kbuild-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

Pull Kbuild fixes from Nicolas Schier:

 - modpost: prevent stack buffer overflow in do_input_entry() and
   do_dmi_entry()

   Defensively replace unbound sprintf() calls in file2alias to prevent
   silent stack overflows and detect alias name overflows with proper
   error message.

 - kbuild: pacman-pkg: make "rc" releases adhere to pacman versioning
   scheme

   Enable smooth upgrades from "rc" releases w/ pacman packages.

* tag 'kbuild-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
  kbuild: pacman-pkg: make "rc" releases adhere to pacman versioning scheme
  modpost: prevent stack buffer overflow in do_input_entry() and do_dmi_entry()

2 files changed, 54 insertions, 27 deletions

diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 4e99393a35f1..2ad87a74bb03 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -651,7 +651,26 @@ static void do_vio_entry(struct module *mod, void *symval)
 	module_alias_printf(mod, true, "%s", alias);
 }
 
-static void do_input(char *alias,
+static void __attribute__((format(printf, 3, 4)))
+alias_append(char *alias, size_t size, const char *fmt, ...)
+{
+	size_t len = strlen(alias);
+	va_list args;
+	int n;
+
+	if (len >= size)
+		fatal("alias buffer (%zu) overflow before append\n", size);
+
+	va_start(args, fmt);
+	n = vsnprintf(alias + len, size - len, fmt, args);
+	va_end(args);
+
+	if (n < 0 || (size_t)n >= size - len)
+		fatal("alias buffer (%zu) overflow on append (need %d, have %zu)\n",
+		      size, n, size - len);
+}
+
+static void do_input(char *alias, size_t size,
 		     kernel_ulong_t *arr, unsigned int min, unsigned int max)
 {
 	unsigned int i;
@@ -659,13 +678,14 @@ static void do_input(char *alias,
 	for (i = min; i <= max; i++)
 		if (get_unaligned_native(arr + i / BITS_PER_LONG) &
 		    (1ULL << (i % BITS_PER_LONG)))
-			sprintf(alias + strlen(alias), "%X,*", i);
+			alias_append(alias, size, "%X,*", i);
 }
 
 /* input:b0v0p0e0-eXkXrXaXmXlXsXfXwX where X is comma-separated %02X. */
 static void do_input_entry(struct module *mod, void *symval)
 {
 	char alias[256] = {};
+	const size_t sizeof_alias = sizeof(alias);
 
 	DEF_FIELD(symval, input_device_id, flags);
 	DEF_FIELD(symval, input_device_id, bustype);
@@ -687,35 +707,35 @@ static void do_input_entry(struct module *mod, void *symval)
 	ADD(alias, "p", flags & INPUT_DEVICE_ID_MATCH_PRODUCT, product);
 	ADD(alias, "e", flags & INPUT_DEVICE_ID_MATCH_VERSION, version);
 
-	sprintf(alias + strlen(alias), "-e*");
+	alias_append(alias, sizeof_alias, "-e*");
 	if (flags & INPUT_DEVICE_ID_MATCH_EVBIT)
-		do_input(alias, *evbit, 0, INPUT_DEVICE_ID_EV_MAX);
-	sprintf(alias + strlen(alias), "k*");
+		do_input(alias, sizeof_alias, *evbit, 0, INPUT_DEVICE_ID_EV_MAX);
+	alias_append(alias, sizeof_alias, "k*");
 	if (flags & INPUT_DEVICE_ID_MATCH_KEYBIT)
-		do_input(alias, *keybit,
+		do_input(alias, sizeof_alias, *keybit,
 			 INPUT_DEVICE_ID_KEY_MIN_INTERESTING,
 			 INPUT_DEVICE_ID_KEY_MAX);
-	sprintf(alias + strlen(alias), "r*");
+	alias_append(alias, sizeof_alias, "r*");
 	if (flags & INPUT_DEVICE_ID_MATCH_RELBIT)
-		do_input(alias, *relbit, 0, INPUT_DEVICE_ID_REL_MAX);
-	sprintf(alias + strlen(alias), "a*");
+		do_input(alias, sizeof_alias, *relbit, 0, INPUT_DEVICE_ID_REL_MAX);
+	alias_append(alias, sizeof_alias, "a*");
 	if (flags & INPUT_DEVICE_ID_MATCH_ABSBIT)
-		do_input(alias, *absbit, 0, INPUT_DEVICE_ID_ABS_MAX);
-	sprintf(alias + strlen(alias), "m*");
+		do_input(alias, sizeof_alias, *absbit, 0, INPUT_DEVICE_ID_ABS_MAX);
+	alias_append(alias, sizeof_alias, "m*");
 	if (flags & INPUT_DEVICE_ID_MATCH_MSCIT)
-		do_input(alias, *mscbit, 0, INPUT_DEVICE_ID_MSC_MAX);
-	sprintf(alias + strlen(alias), "l*");
+		do_input(alias, sizeof_alias, *mscbit, 0, INPUT_DEVICE_ID_MSC_MAX);
+	alias_append(alias, sizeof_alias, "l*");
 	if (flags & INPUT_DEVICE_ID_MATCH_LEDBIT)
-		do_input(alias, *ledbit, 0, INPUT_DEVICE_ID_LED_MAX);
-	sprintf(alias + strlen(alias), "s*");
+		do_input(alias, sizeof_alias, *ledbit, 0, INPUT_DEVICE_ID_LED_MAX);
+	alias_append(alias, sizeof_alias, "s*");
 	if (flags & INPUT_DEVICE_ID_MATCH_SNDBIT)
-		do_input(alias, *sndbit, 0, INPUT_DEVICE_ID_SND_MAX);
-	sprintf(alias + strlen(alias), "f*");
+		do_input(alias, sizeof_alias, *sndbit, 0, INPUT_DEVICE_ID_SND_MAX);
+	alias_append(alias, sizeof_alias, "f*");
 	if (flags & INPUT_DEVICE_ID_MATCH_FFBIT)
-		do_input(alias, *ffbit, 0, INPUT_DEVICE_ID_FF_MAX);
-	sprintf(alias + strlen(alias), "w*");
+		do_input(alias, sizeof_alias, *ffbit, 0, INPUT_DEVICE_ID_FF_MAX);
+	alias_append(alias, sizeof_alias, "w*");
 	if (flags & INPUT_DEVICE_ID_MATCH_SWBIT)
-		do_input(alias, *swbit, 0, INPUT_DEVICE_ID_SW_MAX);
+		do_input(alias, sizeof_alias, *swbit, 0, INPUT_DEVICE_ID_SW_MAX);
 
 	module_alias_printf(mod, false, "input:%s", alias);
 }
@@ -895,12 +915,16 @@ static const struct dmifield {
 	{ NULL,  DMI_NONE }
 };
 
-static void dmi_ascii_filter(char *d, const char *s)
+static void dmi_ascii_filter(char *d, size_t avail, const char *s)
 {
 	/* Filter out characters we don't want to see in the modalias string */
 	for (; *s; s++)
-		if (*s > ' ' && *s < 127 && *s != ':')
+		if (*s > ' ' && *s < 127 && *s != ':') {
+			if (avail <= 1)
+				fatal("%s: alias buffer overflow\n", __func__);
 			*(d++) = *s;
+			avail--;
+		}
 
 	*d = 0;
 }
@@ -909,6 +933,8 @@ static void dmi_ascii_filter(char *d, const char *s)
 static void do_dmi_entry(struct module *mod, void *symval)
 {
 	char alias[256] = {};
+	const size_t sizeof_alias = sizeof(alias);
+	size_t len;
 	int i, j;
 	DEF_FIELD_ADDR(symval, dmi_system_id, matches);
 
@@ -916,11 +942,12 @@ static void do_dmi_entry(struct module *mod, void *symval)
 		for (j = 0; j < 4; j++) {
 			if ((*matches)[j].slot &&
 			    (*matches)[j].slot == dmi_fields[i].field) {
-				sprintf(alias + strlen(alias), ":%s*",
-					dmi_fields[i].prefix);
-				dmi_ascii_filter(alias + strlen(alias),
+				alias_append(alias, sizeof_alias, ":%s*",
+					     dmi_fields[i].prefix);
+				len = strlen(alias);
+				dmi_ascii_filter(alias + len, sizeof_alias - len,
 						 (*matches)[j].substr);
-				strcat(alias, "*");
+				alias_append(alias, sizeof_alias, "*");
 			}
 		}
 	}
diff --git a/scripts/package/PKGBUILD b/scripts/package/PKGBUILD
index 452374d63c24..1213c8e04671 100644
--- a/scripts/package/PKGBUILD
+++ b/scripts/package/PKGBUILD
@@ -10,7 +10,7 @@ for pkg in $_extrapackages; do
 	pkgname+=("${pkgbase}-${pkg}")
 done
 
-pkgver="${KERNELRELEASE//-/_}"
+pkgver="$(echo "${KERNELRELEASE}" | sed 's/-\(rc[0-9]\+\)/\1/;s/-/_/g')"
 # The PKGBUILD is evaluated multiple times.
 # Running scripts/build-version from here would introduce inconsistencies.
 pkgrel="${KBUILD_REVISION}"