Drop the glibc 2.26 fixtures, which no LTS ships (#443)

CHANGELOG.md

@@ -25,6 +25,11 @@ releases are cut by giving that section a version and a date.
 
 ### Changed
 
+- The gem no longer carries gadgets for the three glibc 2.26 builds it shipped
+  (#443). What it carries is the glibc of every Ubuntu LTS in standard support
+  plus the libcs the specs run against, and 2.26 is neither of those any more; a
+  lookup by one of those BuildIDs now answers from the remote database. The
+  entries themselves stay in the repository, as every unshipped build does.
 - Requires elftools >= 2.1.0 (#442), whose faster symbol-table read takes the
   search of a libc with no section headers from 1.11s to 0.68s -- the read
   itself from 0.51s to 0.17s. A libc that still has its sections is unaffected.

aletheia/lib/aletheia/transport.rb

@@ -136,8 +136,7 @@ module Aletheia
       # @param [String] file
       # @return [String?]
       def package_version(file)
-        File.binread(file)[/Ubuntu E?GLIBC (\d[^)]*)/, 1] ||
-          NON_UBUNTU_FIXTURE_VERSIONS[File.basename(file, '.so')]
+        File.binread(file)[/Ubuntu E?GLIBC (\d[^)]*)/, 1]
       end
 
       def stub_built?(dir)
@@ -148,16 +147,6 @@ module Aletheia
         end
       end
 
-      # A few fixtures are plain (non-Ubuntu) glibc builds and carry no "Ubuntu
-      # GLIBC" banner to parse an exact package version from -- e.g.
-      # libc-2.26-2104f3d4...'s banner reads "GNU C Library (GNU libc) stable
-      # release version 2.26", with no Ubuntu package suffix. Recorded by hand
-      # from a same-major.minor sibling fixture that does carry the banner
-      # (same glibc release, so ABI-equivalent for sysroot purposes).
-      NON_UBUNTU_FIXTURE_VERSIONS = {
-        'libc-2.26-2104f3d4ad5cf68603afbe7ba1a17f5ac99c5988' => '2.26-0ubuntu2.1'
-      }.freeze
-
       # Build the per-version sysroot from the fixture's own Ubuntu package version
       # (Ubuntu-sourced fixtures only). Returns whether its park_stub now exists.
       def build_sysroot(dir)

shipped_builds

@@ -6,9 +6,6 @@ libc-2.23-926eb99d49cab2e5622af38ab07395f5b32035e9
 libc-2.23-991d173c6b9056712812d98507cbe95f937db7cf
 libc-2.24-8cba3297f538691eb1875be62986993c004f3f4d
 libc-2.24-fd0655c4d2073eda4235084e1d0e558f0251be8a
-libc-2.26-2104f3d4ad5cf68603afbe7ba1a17f5ac99c5988
-libc-2.26-ddcc13122ddbfe5e5ef77d4ebe66d124ae5762c2
-libc-2.26-f65648a832414f2144ce795d75b6045a1ec2e252
 libc-2.27-53f40c1d2f3739ae017dcdcef1a17314786e3709
 libc-2.27-63b3d43ad45e1b0f601848c65b067f9e9b40528b
 libc-2.27-8c2d375f8d23a7b58de23a60b37bef2d80b23aef

spec/one_gadget_amd64_spec.rb

@@ -73,12 +73,6 @@ describe 'one_gadget_amd64' do
       expect(one_gadget(path)).to eq OneGadget.gadgets(file: path)
     end
 
-    it 'libc-2.26' do
-      path = data_path('libc-2.26-ddcc13122ddbfe5e5ef77d4ebe66d124ae5762c2.so')
-      expect(OneGadget.gadgets(file: path, force_file: true)).to eq [0x47c9a, 0xfccde, 0xfdb8e]
-      expect(one_gadget(path)).to eq OneGadget.gadgets(file: path)
-    end
-
     it 'libc-2.27' do
       path = data_path('libc-2.27-b417c0ba7cc5cf06d1d1bed6652cedb9253c60d0.so')
       expect(OneGadget.gadgets(file: path, force_file: true))

spec/one_gadget_i386_spec.rb

@@ -20,12 +20,6 @@ describe 'one_gadget_i386' do
       expect(OneGadget.gadgets(file: path, force_file: true)).to eq ans
     end
 
-    it 'libc-2.26' do
-      ans = [0x3cc3c, 0x66e7f, 0x66e80, 0x132fbe, 0x132fbf]
-      path = data_path('libc-2.26-f65648a832414f2144ce795d75b6045a1ec2e252.so')
-      expect(OneGadget.gadgets(file: path, force_file: true)).to eq ans
-    end
-
     it 'libc-2.27' do
       ans = [0x3cbf7, 0x6729f, 0x672a0, 0x13573e, 0x13573f]
       path = data_path('libc-2.27-63b3d43ad45e1b0f601848c65b067f9e9b40528b.so')
@@ -67,15 +61,15 @@ describe 'one_gadget_i386' do
         .to include('[[ebp-0x30]] == NULL || [ebp-0x30] == NULL || [ebp-0x30] is a valid envp')
     end
 
-    # 0xbda64's argv pointer is a `lea eax, [ebp-0x28]` alias: the array it builds
+    # 0xbe804's argv pointer is a `lea eax, [ebp-0x28]` alias: the array it builds
     # on the stack is {"/bin/sh", eax, NULL}, with eax an untracked incoming
     # register -- so the same resolve_stack_deref used for envp above applies to
     # argv too, surfacing `eax == NULL` instead of the opaque "[ebp-0x2c] is a
     # valid argv" form.
     it 'resolves argv through a lea-computed alias into the stack frame' do
-      path = data_path('libc-2.26-f65648a832414f2144ce795d75b6045a1ec2e252.so')
+      path = data_path('libc-2.27-63b3d43ad45e1b0f601848c65b067f9e9b40528b.so')
       gadget = OneGadget.gadgets(file: path, force_file: true, details: true, level: 1)
-                        .find { |g| g.offset == 0xbda64 }
+                        .find { |g| g.offset == 0xbe804 }
       expect(gadget.constraints).to include('eax == NULL || {"/bin/sh", eax, NULL} is a valid argv')
     end