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| author | Than McIntosh <thanm@google.com> | 2020-12-15 15:54:25 -0500 |
|---|---|---|
| committer | Than McIntosh <thanm@google.com> | 2020-12-16 14:09:20 +0000 |
| commit | f4e7a6b905ce60448e506a3f6578d01b60602cdd (patch) | |
| tree | 35ed7da80b140f2705510eb59cf1ea1b8c265386 | |
| parent | 75e16f5127eb6affb4b473c93565a8d29a802e51 (diff) | |
| download | go-f4e7a6b905ce60448e506a3f6578d01b60602cdd.tar.gz go-f4e7a6b905ce60448e506a3f6578d01b60602cdd.zip | |
cmd/internal/goobj: fix buglet in object file reader
The code in the new (introduced in 1.15) Go object file reader was
casting a pointer-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 #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>
| -rw-r--r-- | src/cmd/internal/goobj/objfile.go | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/cmd/internal/goobj/objfile.go b/src/cmd/internal/goobj/objfile.go index 6e76bea111..e6447e455d 100644 --- a/src/cmd/internal/goobj/objfile.go +++ b/src/cmd/internal/goobj/objfile.go @@ -483,6 +483,11 @@ func (r *RefFlags) SetFlag2(x uint8) { r[9] = x } func (r *RefFlags) Write(w *Writer) { w.Bytes(r[:]) } +// 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: @@ -792,7 +797,7 @@ func (r *Reader) Reloc(i uint32, j int) *Reloc { func (r *Reader) Relocs(i uint32) []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. @@ -818,7 +823,7 @@ func (r *Reader) Aux(i uint32, j int) *Aux { func (r *Reader) Auxs(i uint32) []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. |