From: Mark Wielaard <mark@klomp.org>
Date: Sat, 28 Dec 2024 00:29:58 +0000 (+0100)
Subject: riscv64: Add hardwire for ld-linux-riscv64-lp64d.so.1 strcmp
X-Git-Tag: VALGRIND_3_25_0~127
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2d09ef48e22061b143cd4765e8defb63f5d5024a;p=thirdparty%2Fvalgrind.git

riscv64: Add hardwire for ld-linux-riscv64-lp64d.so.1 strcmp

When using dlopen ld.so can end up in glibc strcmp_unaligned_loop
which causes undefined reads. Hardwire strcmp for ld.so with a simple
assembly implementation.
---

diff --git a/coregrind/m_redir.c b/coregrind/m_redir.c
index 958f3e7c4..5e7bc42f9 100644
--- a/coregrind/m_redir.c
+++ b/coregrind/m_redir.c
@@ -1714,6 +1714,11 @@ void VG_(redir_initialise) ( void )
          (Addr)&VG_(riscv64_linux_REDIR_FOR_index),
          complain_about_stripped_glibc_ldso
       );
+      add_hardwired_spec(
+         "ld-linux-riscv64-lp64d.so.1", "strcmp",
+         (Addr)&VG_(riscv64_linux_REDIR_FOR_strcmp),
+         complain_about_stripped_glibc_ldso
+      );
    }
 
 #  elif defined(VGP_x86_solaris)
diff --git a/coregrind/m_trampoline.S b/coregrind/m_trampoline.S
index c506070d6..4860a2259 100644
--- a/coregrind/m_trampoline.S
+++ b/coregrind/m_trampoline.S
@@ -1647,6 +1647,23 @@ VG_(riscv64_linux_REDIR_FOR_index):
 	ret
 .size VG_(riscv64_linux_REDIR_FOR_index), .-VG_(riscv64_linux_REDIR_FOR_index)
 
+.global VG_(riscv64_linux_REDIR_FOR_strcmp)
+.type   VG_(riscv64_linux_REDIR_FOR_strcmp), @function
+VG_(riscv64_linux_REDIR_FOR_strcmp):
+0:
+	lbu a5, 0(a0)          /* load *s1 */
+	lbu a4, 0(a1)          /* load *s2 */
+	beqz a5, 1f            /* check end of s1 */
+	beq a5, a4, 2f         /* loop if *s1 == *s2 */
+1:
+	subw a0, a5, a4        /* return value is *s1 - *s2 */
+	ret
+2:
+	addi a0, a0, 1         /* next char in s1 */
+	addi a1, a1, 1         /* next char in s2 */
+        j 0b                   /* and back to the start */
+.size VG_(riscv64_linux_REDIR_FOR_strcmp), .-VG_(riscv64_linux_REDIR_FOR_strcmp)
+
 .global VG_(trampoline_stuff_end)
 VG_(trampoline_stuff_end):
 
diff --git a/coregrind/pub_core_trampoline.h b/coregrind/pub_core_trampoline.h
index 7e9e2d76b..db497c51a 100644
--- a/coregrind/pub_core_trampoline.h
+++ b/coregrind/pub_core_trampoline.h
@@ -180,6 +180,7 @@ extern UInt  VG_(nanomips_linux_REDIR_FOR_strlen)( void* );
 extern Addr   VG_(riscv64_linux_SUBST_FOR_rt_sigreturn);
 extern HChar* VG_(riscv64_linux_REDIR_FOR_index)( const HChar*, Int );
 extern SizeT  VG_(riscv64_linux_REDIR_FOR_strlen)( const HChar* );
+extern Int    VG_(riscv64_linux_REDIR_FOR_strcmp)( const HChar*, const HChar* );
 #endif
 
 #if defined(VGP_x86_solaris)