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| author | Katie Hockman <katie@golang.org> | 2020-11-10 15:54:12 -0500 |
|---|---|---|
| committer | Katie Hockman <katiehockman@google.com> | 2020-11-11 23:35:42 +0000 |
| commit | 84150d0af193a7ccd733b3c7fa5787f43125cd2d (patch) | |
| tree | 4a3a16d190157a2a9dc2cdbea151715ee665278d | |
| parent | ec06b6d6be568ce1591d91a0ea4f14c190d06605 (diff) | |
| download | go-84150d0af193a7ccd733b3c7fa5787f43125cd2d.tar.gz go-84150d0af193a7ccd733b3c7fa5787f43125cd2d.zip | |
[release-branch.go1.15-security] math/big: fix shift for recursive division
The previous s value could cause a crash
for certain inputs.
Will check in tests and documentation improvements later.
Thanks to the Go Ethereum team and the OSS-Fuzz project for reporting this.
Thanks to Rémy Oudompheng and Robert Griesemer for their help
developing and validating the fix.
Fixes CVE-2020-28362
Change-Id: Ibbf455c4436bcdb07c84a34fa6551fb3422356d3
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/899974
Reviewed-by: Roland Shoemaker <bracewell@google.com>
Reviewed-by: Filippo Valsorda <valsorda@google.com>
(cherry picked from commit 28015462c2a83239543dc2bef651e9a5f234b633)
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/901065
| -rw-r--r-- | src/math/big/nat.go | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/math/big/nat.go b/src/math/big/nat.go index 6a3989bf9d8..8c43de69d33 100644 --- a/src/math/big/nat.go +++ b/src/math/big/nat.go @@ -928,7 +928,7 @@ func (z nat) divRecursiveStep(u, v nat, depth int, tmp *nat, temps []*nat) { // Now u < (v<<B), compute lower bits in the same way. // Choose shift = B-1 again. - s := B + s := B - 1 qhat := *temps[depth] qhat.clear() qhat.divRecursiveStep(u[s:].norm(), v[s:], depth+1, tmp, temps) |