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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2022-10-06 12:00:39 +0100
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2022-11-22 14:31:25 +0000
commitde51f7328e62d59f20d7286899a99b35f746dfda (patch)
tree10edd02c138c11819e7907193d073c6b5359d971
parentbd8fac4e2846e0621f87c675d7c609385a4d932d (diff)
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cheri: malloc: add tunable to turn narrowing off
-rw-r--r--elf/dl-tunables.list7
-rw-r--r--malloc/arena.c6
-rw-r--r--manual/tunables.texi6
3 files changed, 19 insertions, 0 deletions
diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list
index e6a56b3070..83f47dcd9a 100644
--- a/elf/dl-tunables.list
+++ b/elf/dl-tunables.list
@@ -159,6 +159,13 @@ glibc {
maxval: 255
security_level: SXID_IGNORE
}
+ cap_narrowing {
+ type: INT_32
+ minval: 0
+ maxval: 1
+ default: 1
+ security_level: SXID_IGNORE
+ }
}
rtld {
diff --git a/malloc/arena.c b/malloc/arena.c
index 894f49b911..85cc2ad066 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -326,6 +326,12 @@ ptmalloc_init (void)
tcache_key_initialize ();
#endif
+#ifdef __CHERI_PURE_CAPABILITY__
+ if (TUNABLE_GET_FULL (glibc, mem, cap_narrowing, int32_t, NULL) == 0)
+ cap_narrowing_enabled = false;
+ else
+ cap_narrowing_enabled = true;
+#endif
cap_init ();
#ifdef USE_MTAG
diff --git a/manual/tunables.texi b/manual/tunables.texi
index 83cdcdac6d..ffe0202627 100644
--- a/manual/tunables.texi
+++ b/manual/tunables.texi
@@ -612,3 +612,9 @@ support in the kernel if this tunable has any non-zero value.
The default value is @samp{0}, which disables all memory tagging.
@end deftp
+
+@deftp Tunable glibc.mem.cap_narrowing
+On CHERI architecture use capability bounds narrowing in the malloc
+implementation. By default it is set to 1, to disable bounds narrowing
+set it to 0.
+@end deftp