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authorKevin Cernekee <cernekee@gmail.com>2011-07-24 01:19:13 -0700
committerCarmelo Amoroso <carmelo.amoroso@st.com>2011-07-27 09:40:24 +0200
commita2f827c7c28c955ad49b32909452e42ccfc5e5c1 (patch)
tree6da4313f89a4308e1c7ee1151a92ab210301d954
parent2d4243ce60bcd7a9f64c2ce670bc456f2c7da708 (diff)
ldso/mips: dlsym() incorrectly matches undefined symbols
check_match() relies on checking for (sym->st_value == 0) to see if the symbol is undefined. This works reasonably well on most architectures, such as ARM or i386: $ readelf -s /lib32/libcap.so.2 | grep -E "\<malloc\>" 17: 00000000 0 FUNC GLOBAL DEFAULT UND malloc@GLIBC_2.0 (2) However, on MIPS, libbfd puts nonzero data in the st_value field to facilitate resetting the symbol's GOT entry if the library that defines the symbol gets unloaded: $ mipsel-linux-readelf -s libfoo.so | grep -E "\<malloc\>" 74: 00003140 0 FUNC GLOBAL DEFAULT UND malloc This can cause check_match to report a false positive when examining the external symbol reference. Consequently dlsym() will return a bad pointer to the caller. Use the special MIPS logic from glibc-ports-2.13 to avoid this situation. Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>
-rw-r--r--ldso/ldso/dl-hash.c4
-rw-r--r--ldso/ldso/mips/dl-sysdep.h3
2 files changed, 7 insertions, 0 deletions
diff --git a/ldso/ldso/dl-hash.c b/ldso/ldso/dl-hash.c
index 2ec883a86..9b671564f 100644
--- a/ldso/ldso/dl-hash.c
+++ b/ldso/ldso/dl-hash.c
@@ -188,6 +188,10 @@ check_match (const ElfW(Sym) *sym, char *strtab, const char* undef_name, int typ
*/
return NULL;
#endif
+#ifdef ARCH_SKIP_RELOC
+ if (ARCH_SKIP_RELOC(type_class, sym))
+ return NULL;
+#endif
if (_dl_strcmp(strtab + sym->st_name, undef_name) != 0)
return NULL;
diff --git a/ldso/ldso/mips/dl-sysdep.h b/ldso/ldso/mips/dl-sysdep.h
index 80c089aed..e61c6ecae 100644
--- a/ldso/ldso/mips/dl-sysdep.h
+++ b/ldso/ldso/mips/dl-sysdep.h
@@ -113,6 +113,9 @@ else if ((dpnt->d_tag == DT_MIPS_RLD_MAP) && (dpnt->d_un.d_ptr)) \
*(ElfW(Addr) *)(dpnt->d_un.d_ptr) = (ElfW(Addr)) debug_addr; \
} while (0)
+#define ARCH_SKIP_RELOC(type_class, sym) \
+ ((sym)->st_shndx == SHN_UNDEF && !((sym)->st_other & STO_MIPS_PLT))
+
/* Initialization sequence for the application/library GOT. */
#define INIT_GOT(GOT_BASE,MODULE) \
do { \