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authorRich Felker <dalias@aerifal.cx>2023-02-09 11:52:44 -0500
committerRich Felker <dalias@aerifal.cx>2023-02-09 12:33:35 -0500
commit269d193820342dc109f39909d78fb30f4c978f76 (patch)
tree2acbae503e21dca93feb669b5d5a890ee915a797 /src
parentea3b40a321e751e016948087ef23ae7b9e8e0150 (diff)
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fix wrong sigaction syscall ABI on mips*, or1k, microblaze, riscv64
we wrongly defined a dummy SA_RESTORER flag on these archs, despite the kernel interface not actually having such a feature. on archs which lack SA_RESTORER, the kernel sigaction structure also lacks the restorer function pointer member, which means the signal mask appears at a different offset. the kernel was thereby interpreting the bits of the code address as part of the signal set to be masked while handling the signal. this patch removes the erroneous SA_RESTORER definitions from archs which do not have it, makes access to the member conditional on whether SA_RESTORER is defined for the arch, and removes the now-unused asm for the affected archs. because there are reportedly versions of qemu-user which also use the wrong ABI here, the old ksigaction struct size is preserved with an unused member at the end. this is harmless and mitigates the risk of such a bug turning into a buffer overflow onto the sigaction function's stack.
Diffstat (limited to 'src')
-rw-r--r--src/internal/ksigaction.h5
-rw-r--r--src/signal/mips/restore.s15
-rw-r--r--src/signal/mips64/restore.s11
-rw-r--r--src/signal/mipsn32/restore.s11
-rw-r--r--src/signal/sigaction.c5
5 files changed, 9 insertions, 38 deletions
diff --git a/src/internal/ksigaction.h b/src/internal/ksigaction.h
index 8ebd5938..ef333f33 100644
--- a/src/internal/ksigaction.h
+++ b/src/internal/ksigaction.h
@@ -6,8 +6,13 @@
struct k_sigaction {
void (*handler)(int);
unsigned long flags;
+#ifdef SA_RESTORER
void (*restorer)(void);
+#endif
unsigned mask[2];
+#ifndef SA_RESTORER
+ void *unused;
+#endif
};
hidden void __restore(), __restore_rt();
diff --git a/src/signal/mips/restore.s b/src/signal/mips/restore.s
deleted file mode 100644
index b6dadce0..00000000
--- a/src/signal/mips/restore.s
+++ /dev/null
@@ -1,15 +0,0 @@
-.set noreorder
-
-.global __restore_rt
-.hidden __restore_rt
-.type __restore_rt,@function
-__restore_rt:
- li $2, 4193
- syscall
-
-.global __restore
-.hidden __restore
-.type __restore,@function
-__restore:
- li $2, 4119
- syscall
diff --git a/src/signal/mips64/restore.s b/src/signal/mips64/restore.s
deleted file mode 100644
index 401f8e73..00000000
--- a/src/signal/mips64/restore.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.set noreorder
-.global __restore_rt
-.global __restore
-.hidden __restore_rt
-.hidden __restore
-.type __restore_rt,@function
-.type __restore,@function
-__restore_rt:
-__restore:
- li $2,5211
- syscall
diff --git a/src/signal/mipsn32/restore.s b/src/signal/mipsn32/restore.s
deleted file mode 100644
index 4cd4e1b4..00000000
--- a/src/signal/mipsn32/restore.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.set noreorder
-.global __restore_rt
-.global __restore
-.hidden __restore_rt
-.hidden __restore
-.type __restore_rt,@function
-.type __restore,@function
-__restore_rt:
-__restore:
- li $2,6211
- syscall
diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c
index 2203471b..e45308fa 100644
--- a/src/signal/sigaction.c
+++ b/src/signal/sigaction.c
@@ -44,8 +44,11 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
}
}
ksa.handler = sa->sa_handler;
- ksa.flags = sa->sa_flags | SA_RESTORER;
+ ksa.flags = sa->sa_flags;
+#ifdef SA_RESTORER
+ ksa.flags |= SA_RESTORER;
ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
+#endif
memcpy(&ksa.mask, &sa->sa_mask, _NSIG/8);
}
int r = __syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, _NSIG/8);