Completely quote AppPath and CustomConf paths (#12955)
* Completely quote AppPath and CustomConf paths Properly handle spaces in AppPath and CustomConf within hooks and authorized_keys. Unfortunately here we don't seem to be able to get away with using go-shellquote as it appears that Windows doesn't play too well with singlequote quoting - therefore we will avoid singlequote quoting unless we absolutely cannot get away without it, e.g. \n or !. Fix #10813 Signed-off-by: Andrew Thornton <art27@cantab.net> * missing change Signed-off-by: Andrew Thornton <art27@cantab.net> * fix Test_CmdKeys Signed-off-by: Andrew Thornton <art27@cantab.net>tokarchuk/v1.17
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// Copyright 2020 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package util |
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import "strings" |
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// Bash has the definition of a metacharacter:
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// * A character that, when unquoted, separates words.
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// A metacharacter is one of: " \t\n|&;()<>"
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//
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// The following characters also have addition special meaning when unescaped:
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// * ‘${[*?!"'`\’
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//
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// Double Quotes preserve the literal value of all characters with then quotes
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// excepting: ‘$’, ‘`’, ‘\’, and, when history expansion is enabled, ‘!’.
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// The backslash retains its special meaning only when followed by one of the
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// following characters: ‘$’, ‘`’, ‘"’, ‘\’, or newline.
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// Backslashes preceding characters without a special meaning are left
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// unmodified. A double quote may be quoted within double quotes by preceding
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// it with a backslash. If enabled, history expansion will be performed unless
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// an ‘!’ appearing in double quotes is escaped using a backslash. The
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// backslash preceding the ‘!’ is not removed.
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//
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// -> This means that `!\n` cannot be safely expressed in `"`.
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//
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// Looking at the man page for Dash and ash the situation is similar.
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//
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// Now zsh requires that ‘}’, and ‘]’ are also enclosed in doublequotes or escaped
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//
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// Single quotes escape everything except a ‘'’
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//
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// There's one other gotcha - ‘~’ at the start of a string needs to be expanded
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// because people always expect that - of course if there is a special character before '/'
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// this is not going to work
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const ( |
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tildePrefix = '~' |
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needsEscape = " \t\n|&;()<>${}[]*?!\"'`\\" |
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needsSingleQuote = "!\n" |
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) |
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var doubleQuoteEscaper = strings.NewReplacer(`$`, `\$`, "`", "\\`", `"`, `\"`, `\`, `\\`) |
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var singleQuoteEscaper = strings.NewReplacer(`'`, `'\''`) |
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var singleQuoteCoalescer = strings.NewReplacer(`''\'`, `\'`, `\'''`, `\'`) |
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// ShellEscape will escape the provided string.
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// We can't just use go-shellquote here because our preferences for escaping differ from those in that we want:
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//
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// * If the string doesn't require any escaping just leave it as it is.
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// * If the string requires any escaping prefer double quote escaping
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// * If we have ! or newlines then we need to use single quote escaping
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func ShellEscape(toEscape string) string { |
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if len(toEscape) == 0 { |
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return toEscape |
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} |
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start := 0 |
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if toEscape[0] == tildePrefix { |
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// We're in the forcibly non-escaped section...
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idx := strings.IndexRune(toEscape, '/') |
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if idx < 0 { |
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idx = len(toEscape) |
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} else { |
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idx++ |
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} |
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if !strings.ContainsAny(toEscape[:idx], needsEscape) { |
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// We'll assume that they intend ~ expansion to occur
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start = idx |
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} |
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} |
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// Now for simplicity we'll look at the rest of the string
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if !strings.ContainsAny(toEscape[start:], needsEscape) { |
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return toEscape |
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} |
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// OK we have to do some escaping
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sb := &strings.Builder{} |
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_, _ = sb.WriteString(toEscape[:start]) |
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// Do we have any characters which absolutely need to be within single quotes - that is simply ! or \n?
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if strings.ContainsAny(toEscape[start:], needsSingleQuote) { |
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// We need to single quote escape.
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sb2 := &strings.Builder{} |
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_, _ = sb2.WriteRune('\'') |
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_, _ = singleQuoteEscaper.WriteString(sb2, toEscape[start:]) |
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_, _ = sb2.WriteRune('\'') |
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_, _ = singleQuoteCoalescer.WriteString(sb, sb2.String()) |
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return sb.String() |
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} |
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// OK we can just use " just escape the things that need escaping
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_, _ = sb.WriteRune('"') |
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_, _ = doubleQuoteEscaper.WriteString(sb, toEscape[start:]) |
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_, _ = sb.WriteRune('"') |
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return sb.String() |
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} |
@ -0,0 +1,92 @@ |
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// Copyright 2020 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package util |
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import "testing" |
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func TestShellEscape(t *testing.T) { |
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tests := []struct { |
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name string |
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toEscape string |
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want string |
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}{ |
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{ |
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"Simplest case - nothing to escape", |
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"a/b/c/d", |
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"a/b/c/d", |
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}, { |
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"Prefixed tilde - with normal stuff - should not escape", |
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"~/src/go/gitea/gitea", |
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"~/src/go/gitea/gitea", |
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}, { |
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"Typical windows path with spaces - should get doublequote escaped", |
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`C:\Program Files\Gitea v1.13 - I like lots of spaces\gitea`, |
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`"C:\\Program Files\\Gitea v1.13 - I like lots of spaces\\gitea"`, |
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}, { |
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"Forward-slashed windows path with spaces - should get doublequote escaped", |
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"C:/Program Files/Gitea v1.13 - I like lots of spaces/gitea", |
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`"C:/Program Files/Gitea v1.13 - I like lots of spaces/gitea"`, |
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}, { |
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"Prefixed tilde - but then a space filled path", |
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"~git/Gitea v1.13/gitea", |
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`~git/"Gitea v1.13/gitea"`, |
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}, { |
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"Bangs are unforutunately not predictable so need to be singlequoted", |
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"C:/Program Files/Gitea!/gitea", |
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`'C:/Program Files/Gitea!/gitea'`, |
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}, { |
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"Newlines are just irritating", |
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"/home/git/Gitea\n\nWHY-WOULD-YOU-DO-THIS\n\nGitea/gitea", |
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"'/home/git/Gitea\n\nWHY-WOULD-YOU-DO-THIS\n\nGitea/gitea'", |
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}, { |
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"Similarly we should nicely handle mutiple single quotes if we have to single-quote", |
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"'!''!'''!''!'!'", |
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`\''!'\'\''!'\'\'\''!'\'\''!'\''!'\'`, |
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}, { |
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"Double quote < ...", |
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"~/<gitea", |
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"~/\"<gitea\"", |
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}, { |
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"Double quote > ...", |
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"~/gitea>", |
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"~/\"gitea>\"", |
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}, { |
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"Double quote and escape $ ...", |
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"~/$gitea", |
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"~/\"\\$gitea\"", |
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}, { |
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"Double quote {...", |
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"~/{gitea", |
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"~/\"{gitea\"", |
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}, { |
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"Double quote }...", |
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"~/gitea}", |
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"~/\"gitea}\"", |
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}, { |
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"Double quote ()...", |
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"~/(gitea)", |
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"~/\"(gitea)\"", |
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}, { |
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"Double quote and escape `...", |
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"~/gitea`", |
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"~/\"gitea\\`\"", |
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}, { |
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"Double quotes can handle a number of things without having to escape them but not everything ...", |
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"~/<gitea> ${gitea} `gitea` [gitea] (gitea) \"gitea\" \\gitea\\ 'gitea'", |
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"~/\"<gitea> \\${gitea} \\`gitea\\` [gitea] (gitea) \\\"gitea\\\" \\\\gitea\\\\ 'gitea'\"", |
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}, { |
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"Single quotes don't need to escape except for '...", |
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"~/<gitea> ${gitea} `gitea` (gitea) !gitea! \"gitea\" \\gitea\\ 'gitea'", |
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"~/'<gitea> ${gitea} `gitea` (gitea) !gitea! \"gitea\" \\gitea\\ '\\''gitea'\\'", |
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}, |
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} |
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for _, tt := range tests { |
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t.Run(tt.name, func(t *testing.T) { |
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if got := ShellEscape(tt.toEscape); got != tt.want { |
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t.Errorf("ShellEscape(%q):\nGot: %s\nWanted: %s", tt.toEscape, got, tt.want) |
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} |
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}) |
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} |
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} |
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