fix the symbol value for a dynamic relocation referencing a SHN_ABS symbol

Submitted by Fangrui Song on April 3, 2020, 6:28 a.m.

Details

Message ID 20200403062803.wmxb46mnfhwalaet@gmail.com
State New
Series "fix the symbol value for a dynamic relocation referencing a SHN_ABS symbol"
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Commit Message

Fangrui Song April 3, 2020, 6:28 a.m.
fixes the example at https://sourceware.org/bugzilla/show_bug.cgi?id=19818#c3


the glibc bug also mentions dladdr() but that change seems more disruptive and
i am now sure whether/how that should be fixed.

---
 ldso/dynlink.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

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diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index afec985a..6f4b50c9 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -403,7 +403,10 @@  static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
 			def.dso = dso;
 		}
 
-		sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
+		sym_val = def.sym
+			? def.sym->st_shndx == SHN_ABS ? def.sym->st_value
+				: (size_t)laddr(def.dso, def.sym->st_value)
+			: 0;
 		tls_val = def.sym ? def.sym->st_value : 0;
 
 		if ((type == REL_TPOFF || type == REL_TPOFF_NEG)