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| author | Than McIntosh <thanm@google.com> | 2020-12-15 15:54:25 -0500 |
|---|---|---|
| committer | Carlos Amedee <carlos@golang.org> | 2021-02-02 22:36:08 +0000 |
| commit | 58dc4452620ebefa75742661c538b8406b213b4a (patch) | |
| tree | f9d151454f766752f0492ef8b9ec4a939e932598 | |
| parent | aa9b48cd1837644a1555fd7a370800924cef627a (diff) | |
| download | go-58dc4452620ebefa75742661c538b8406b213b4a.tar.gz go-58dc4452620ebefa75742661c538b8406b213b4a.zip | |
[release-branch.go1.15] cmd/internal/goobj2: fix buglet in object file reader
The code in the Go object file reader was casting a pointer to mmaped
memory into a large array prior to performing a read of the
relocations section:
return (*[1<<20]Reloc)(unsafe.Pointer(&r.b[off]))[:n:n]
For very large object files, this artificial array isn't large enough
(that is, there are more than 1048576 relocs to read), so update the
code to use a larger artifical array size.
Fixes #43214.
Updates #41621.
Change-Id: Ic047c8aef4f8a3839f2e7e3594bce652ebd6bd5b
Reviewed-on: https://go-review.googlesource.com/c/go/+/278492
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Trust: Than McIntosh <thanm@google.com>
(cherry picked from commit f4e7a6b905ce60448e506a3f6578d01b60602cdd)
Reviewed-on: https://go-review.googlesource.com/c/go/+/278673
| -rw-r--r-- | src/cmd/internal/goobj2/objfile.go | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/cmd/internal/goobj2/objfile.go b/src/cmd/internal/goobj2/objfile.go index 7f728e4f766..aba9b9856e2 100644 --- a/src/cmd/internal/goobj2/objfile.go +++ b/src/cmd/internal/goobj2/objfile.go @@ -379,6 +379,11 @@ func (a *Aux) Write(w *Writer) { w.Bytes(a[:]) } // for testing func (a *Aux) fromBytes(b []byte) { copy(a[:], b) } +// Used to construct an artifically large array type when reading an +// item from the object file relocs section or aux sym section (needs +// to work on 32-bit as well as 64-bit). See issue 41621. +const huge = (1<<31 - 1) / RelocSize + // Referenced symbol name. // // Serialized format: @@ -652,7 +657,7 @@ func (r *Reader) Reloc(i int, j int) *Reloc { func (r *Reader) Relocs(i int) []Reloc { off := r.RelocOff(i, 0) n := r.NReloc(i) - return (*[1 << 20]Reloc)(unsafe.Pointer(&r.b[off]))[:n:n] + return (*[huge]Reloc)(unsafe.Pointer(&r.b[off]))[:n:n] } // NAux returns the number of aux symbols of the i-th symbol. @@ -678,7 +683,7 @@ func (r *Reader) Aux(i int, j int) *Aux { func (r *Reader) Auxs(i int) []Aux { off := r.AuxOff(i, 0) n := r.NAux(i) - return (*[1 << 20]Aux)(unsafe.Pointer(&r.b[off]))[:n:n] + return (*[huge]Aux)(unsafe.Pointer(&r.b[off]))[:n:n] } // DataOff returns the offset of the i-th symbol's data. |