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172 lines
6.3 KiB
172 lines
6.3 KiB
BASH PATCH REPORT
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=================
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Bash-Release: 5.0
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Patch-ID: bash50-010
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Bug-Reported-by: Thorsten Glaser <tg@mirbsd.de>
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Bug-Reference-ID: <156622962831.19438.16374961114836556294.reportbug@tglase.lan.tarent.de>
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Bug-Reference-URL: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=935115
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Bug-Description:
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Bash-5.0 changed the way assignment statements preceding special builtins
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and shell functions were handled in posix mode. They automatically created
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or modified global variables instead of modifying existing local variables
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as in bash-4.4.
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The bash-4.4 posix-mode semantics were buggy, and resulted in creating
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local variables where they were not intended and modifying global variables
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and local variables simultaneously.
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The bash-5.0 changes were intended to fix this issue, but did not preserve
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enough backwards compatibility. The posix standard also changed what it
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required in these cases, so bash-5.0 is not bound by the strict conformance
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requirements that existed in previous issues of the standard.
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This patch modifies the bash-5.0 posix mode behavior in an effort to restore
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some backwards compatibility and rationalize the behavior in the presence of
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local variables. It
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1. Changes the assignment semantics to be more similar to standalone assignment
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statements: assignments preceding a function call or special builtin while
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executing in a shell function will modify the value of a local variable
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with the same name for the duration of the function's execution;
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2. Changes assignments preceding shell function calls or special builtins
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from within a shell function to no longer create or modify global variables
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in the presence of a local variable with the same name;
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3. Assignment statements preceding a shell function call or special builtin
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at the global scope continue to modify the (global) calling environment,
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but are unaffected by assignments preceding function calls or special
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builtins within a function, as described in item 2. This is also similar
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to the behavior of a standalone assignment statement.
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Patch (apply with `patch -p0'):
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*** ../bash-5.0-patched/variables.c 2018-12-18 11:07:21.000000000 -0500
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--- variables.c 2019-08-22 10:53:44.000000000 -0400
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***************
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*** 4461,4467 ****
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/* Take a variable from an assignment statement preceding a posix special
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! builtin (including `return') and create a global variable from it. This
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! is called from merge_temporary_env, which is only called when in posix
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! mode. */
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static void
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push_posix_temp_var (data)
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--- 4461,4467 ----
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/* Take a variable from an assignment statement preceding a posix special
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! builtin (including `return') and create a variable from it as if a
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! standalone assignment statement had been performed. This is called from
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! merge_temporary_env, which is only called when in posix mode. */
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static void
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push_posix_temp_var (data)
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***************
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*** 4473,4486 ****
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var = (SHELL_VAR *)data;
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! binding_table = global_variables->table;
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! if (binding_table == 0)
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! binding_table = global_variables->table = hash_create (VARIABLES_HASH_BUCKETS);
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!
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! v = bind_variable_internal (var->name, value_cell (var), binding_table, 0, ASS_FORCE|ASS_NOLONGJMP);
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/* global variables are no longer temporary and don't need propagating. */
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! var->attributes &= ~(att_tempvar|att_propagate);
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if (v)
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! v->attributes |= var->attributes;
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if (find_special_var (var->name) >= 0)
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--- 4473,4497 ----
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var = (SHELL_VAR *)data;
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! /* Just like do_assignment_internal(). This makes assignments preceding
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! special builtins act like standalone assignment statements when in
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! posix mode, satisfying the posix requirement that this affect the
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! "current execution environment." */
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! v = bind_variable (var->name, value_cell (var), ASS_FORCE|ASS_NOLONGJMP);
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!
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! /* If this modifies an existing local variable, v->context will be non-zero.
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! If it comes back with v->context == 0, we bound at the global context.
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! Set binding_table appropriately. It doesn't matter whether it's correct
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! if the variable is local, only that it's not global_variables->table */
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! binding_table = v->context ? shell_variables->table : global_variables->table;
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/* global variables are no longer temporary and don't need propagating. */
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! if (binding_table == global_variables->table)
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! var->attributes &= ~(att_tempvar|att_propagate);
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!
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if (v)
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! {
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! v->attributes |= var->attributes;
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! v->attributes &= ~att_tempvar; /* not a temp var now */
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! }
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if (find_special_var (var->name) >= 0)
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***************
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*** 4576,4587 ****
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{
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int i;
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tempvar_list = strvec_create (HASH_ENTRIES (temporary_env) + 1);
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tempvar_list[tvlist_ind = 0] = 0;
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!
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! hash_flush (temporary_env, pushf);
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! hash_dispose (temporary_env);
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temporary_env = (HASH_TABLE *)NULL;
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tempvar_list[tvlist_ind] = 0;
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--- 4587,4601 ----
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{
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int i;
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+ HASH_TABLE *disposer;
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tempvar_list = strvec_create (HASH_ENTRIES (temporary_env) + 1);
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tempvar_list[tvlist_ind = 0] = 0;
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!
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! disposer = temporary_env;
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temporary_env = (HASH_TABLE *)NULL;
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+ hash_flush (disposer, pushf);
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+ hash_dispose (disposer);
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+
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tempvar_list[tvlist_ind] = 0;
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*** ../bash-5.0-patched/tests/varenv.right 2018-12-17 15:39:48.000000000 -0500
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--- tests/varenv.right 2019-08-22 16:05:25.000000000 -0400
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***************
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*** 147,153 ****
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outside: declare -- var="one"
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inside: declare -x var="value"
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! outside: declare -x var="value"
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! inside: declare -- var="local"
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! outside: declare -x var="global"
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foo=<unset> environment foo=
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foo=foo environment foo=foo
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--- 147,153 ----
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outside: declare -- var="one"
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inside: declare -x var="value"
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! outside: declare -- var="outside"
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! inside: declare -x var="global"
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! outside: declare -- var="outside"
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foo=<unset> environment foo=
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foo=foo environment foo=foo
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*** ../bash-5.0/patchlevel.h 2016-06-22 14:51:03.000000000 -0400
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--- patchlevel.h 2016-10-01 11:01:28.000000000 -0400
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***************
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*** 26,30 ****
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looks for to find the patch level (for the sccs version string). */
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! #define PATCHLEVEL 9
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#endif /* _PATCHLEVEL_H_ */
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--- 26,30 ----
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looks for to find the patch level (for the sccs version string). */
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! #define PATCHLEVEL 10
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#endif /* _PATCHLEVEL_H_ */
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