[Tarantool-patches] [PATCH v1 1/1] sql: fix error on copy empty string in mem_copy()
Mergen Imeev
imeevma at tarantool.org
Mon Aug 30 08:57:06 MSK 2021
Thank you for the review! My answers, diff and new patch below.
On Fri, Aug 27, 2021 at 11:44:23PM +0200, Vladislav Shpilevoy wrote:
> Thanks for the fixes!
>
> See 3 comments below.
>
> > sql: fix error on copy empty string in mem_copy()
> >
> > This patch fixes the problem with copying an empty string in mem_copy().
> > Previously, because the string length was 0, an error was thrown, but
> > the diag was not set, which could lead to an error due to an empty diag
> > or to a double free.
> >
> > Closes #6157
>
> 1. You also need to add closes 6399, don't you?
>
True, thank you. Fixed.
> > diff --git a/src/box/sql/vdbeaux.c b/src/box/sql/vdbeaux.c
> > index 2d7800b17..beb8cee04 100644
> > --- a/src/box/sql/vdbeaux.c
> > +++ b/src/box/sql/vdbeaux.c
> > @@ -2318,8 +2318,12 @@ sqlVdbeGetBoundValue(struct Vdbe *v, int iVar)
> > Mem *pMem = &v->aVar[iVar - 1];
> > if (!mem_is_null(pMem)) {
> > sql_value *pRet = sqlValueNew(v->db);
> > - if (pRet != NULL)
> > - mem_copy(pRet, pMem);
> > + if (pRet == NULL)
> > + return NULL;
> > + if (mem_copy(pRet, pMem) != 0) {
> > + sqlDbFree(sql_get(), pRet);
>
> 2. Shouldn't you use sqlValueFree()?
>
True, fixed.
> > + return NULL;
> > + }
> > return pRet;
> > }
> > }
> > diff --git a/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
> > new file mode 100755
> > index 000000000..e0c09a325
> > --- /dev/null
> > +++ b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
> > @@ -0,0 +1,18 @@
> > +#!/usr/bin/env tarantool
> > +local tap = require('tap')
> > +local test = tap.test('test wrong error in mem_copy()')
> > +
> > +--
> > +-- Make sure there is no assert due to an incorrectly set error in mem_copy().
> > +-- How this test works: We have 128 mempool cells in SQL ("lookaside"), and
> > +-- until those 128 cells are filled in, the error cannot be reproduced. Also, we
> > +-- have to get '' from somewhere because if we just enter it, it will be of type
> > +-- STATIC and no memory will be allocated.
>
> 3. You mention 128 cells, but I don't see how 128 or something close is used
> in this test.
>
Fixed. Increased number of expressions to 129 and reworked the test-file a bit.
> > +--
> > +local s = "NULLIF(SUBSTR('123', 1, 0), NULL)"
> > +for i = 1, 5 do s = s..', '..s end
> > +local res = box.execute("SELECT "..s).rows[1]
> > +
> > +test:plan(1)
> > +test:is(#res, 32, 'wrong error in mem_copy() was set')
> > +os.exit(test:check() and 0 or 1)
Diff:
diff --git a/src/box/sql/vdbeaux.c b/src/box/sql/vdbeaux.c
index beb8cee04..8148ed8b0 100644
--- a/src/box/sql/vdbeaux.c
+++ b/src/box/sql/vdbeaux.c
@@ -2321,7 +2321,7 @@ sqlVdbeGetBoundValue(struct Vdbe *v, int iVar)
if (pRet == NULL)
return NULL;
if (mem_copy(pRet, pMem) != 0) {
- sqlDbFree(sql_get(), pRet);
+ sqlValueFree(pRet);
return NULL;
}
return pRet;
diff --git a/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
index e0c09a325..e2d25d7d4 100755
--- a/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
+++ b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
@@ -1,6 +1,6 @@
#!/usr/bin/env tarantool
-local tap = require('tap')
-local test = tap.test('test wrong error in mem_copy()')
+local test = require("sqltester")
+test:plan(1)
--
-- Make sure there is no assert due to an incorrectly set error in mem_copy().
@@ -10,9 +10,20 @@ local test = tap.test('test wrong error in mem_copy()')
-- STATIC and no memory will be allocated.
--
local s = "NULLIF(SUBSTR('123', 1, 0), NULL)"
-for i = 1, 5 do s = s..', '..s end
-local res = box.execute("SELECT "..s).rows[1]
+for i = 1, 7 do s = s..', '..s end
+s = "SELECT "..s..', '.."NULLIF(SUBSTR('123', 1, 0), NULL)"
+-- The "s" variable contains 129 expressions.
-test:plan(1)
-test:is(#res, 32, 'wrong error in mem_copy() was set')
-os.exit(test:check() and 0 or 1)
+test:do_execsql_test(
+ "gh-6157", s, {
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", ""
+ })
+
+test:finish_test()
New patch:
commit a27b5651b67b54ddf9d403847263235162fbf489
Author: Mergen Imeev <imeevma at gmail.com>
Date: Mon Aug 23 11:54:09 2021 +0300
sql: fix error on copy empty string in mem_copy()
This patch fixes the problem with copying an empty string in mem_copy().
Previously, because the string length was 0, an error was thrown, but
the diag was not set, which could lead to an error due to an empty diag
or to a double free.
Closes #6157
Closes #6399
diff --git a/changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md b/changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md
new file mode 100644
index 000000000..e5f747414
--- /dev/null
+++ b/changelogs/unreleased/gh-6157-fix-error-on-copy-empty-str.md
@@ -0,0 +1,5 @@
+## bugfix/sql
+
+* Now, when copying an empty string, an error will not be set
+ unnecessarily (gh-6157).
+
diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index c063552d6..9009f9e4f 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -1771,13 +1771,15 @@ minmaxStep(sql_context * context, int NotUsed, sql_value ** argv)
bool is_max = (func->flags & SQL_FUNC_MAX) != 0;
int cmp = mem_cmp_scalar(pBest, pArg, pColl);
if ((is_max && cmp < 0) || (!is_max && cmp > 0)) {
- mem_copy(pBest, pArg);
+ if (mem_copy(pBest, pArg) != 0)
+ context->is_aborted = true;
} else {
sqlSkipAccumulatorLoad(context);
}
} else {
pBest->db = sql_context_db_handle(context);
- mem_copy(pBest, pArg);
+ if (mem_copy(pBest, pArg) != 0)
+ context->is_aborted = true;
}
}
diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
index 4c40f15dc..819d9b094 100644
--- a/src/box/sql/mem.c
+++ b/src/box/sql/mem.c
@@ -1913,7 +1913,8 @@ mem_copy(struct Mem *to, const struct Mem *from)
assert((to->flags & MEM_Zero) == 0 || to->type == MEM_TYPE_BIN);
if ((to->flags & MEM_Zero) != 0)
return sqlVdbeMemExpandBlob(to);
- to->zMalloc = sqlDbReallocOrFree(to->db, to->zMalloc, to->n);
+ to->zMalloc = sqlDbRealloc(to->db, to->zMalloc, MAX(32, to->n));
+ assert(to->zMalloc != NULL || sql_get()->mallocFailed != 0);
if (to->zMalloc == NULL)
return -1;
to->szMalloc = sqlDbMallocSize(to->db, to->zMalloc);
diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
index 7f86fa7b3..44533fb3e 100644
--- a/src/box/sql/vdbe.c
+++ b/src/box/sql/vdbe.c
@@ -978,7 +978,8 @@ case OP_Copy: {
pOut = &aMem[pOp->p2];
assert(pOut!=pIn1);
while( 1) {
- mem_copy(pOut, pIn1);
+ if (mem_copy(pOut, pIn1) != 0)
+ goto abort_due_to_error;
REGISTER_TRACE(p, pOp->p2+pOp->p3-n, pOut);
if ((n--)==0) break;
pOut++;
diff --git a/src/box/sql/vdbeapi.c b/src/box/sql/vdbeapi.c
index 8031ee0dc..e44d73a16 100644
--- a/src/box/sql/vdbeapi.c
+++ b/src/box/sql/vdbeapi.c
@@ -232,7 +232,8 @@ sql_result_text64(sql_context * pCtx,
void
sql_result_value(sql_context * pCtx, sql_value * pValue)
{
- mem_copy(pCtx->pOut, pValue);
+ if (mem_copy(pCtx->pOut, pValue) != 0)
+ pCtx->is_aborted = true;
}
void
diff --git a/src/box/sql/vdbeaux.c b/src/box/sql/vdbeaux.c
index 2d7800b17..8148ed8b0 100644
--- a/src/box/sql/vdbeaux.c
+++ b/src/box/sql/vdbeaux.c
@@ -2318,8 +2318,12 @@ sqlVdbeGetBoundValue(struct Vdbe *v, int iVar)
Mem *pMem = &v->aVar[iVar - 1];
if (!mem_is_null(pMem)) {
sql_value *pRet = sqlValueNew(v->db);
- if (pRet != NULL)
- mem_copy(pRet, pMem);
+ if (pRet == NULL)
+ return NULL;
+ if (mem_copy(pRet, pMem) != 0) {
+ sqlValueFree(pRet);
+ return NULL;
+ }
return pRet;
}
}
diff --git a/test/sql-tap/engine.cfg b/test/sql-tap/engine.cfg
index 587adbed9..c35d1dced 100644
--- a/test/sql-tap/engine.cfg
+++ b/test/sql-tap/engine.cfg
@@ -35,6 +35,7 @@
"built-in-functions.test.lua": {
"memtx": {"engine": "memtx"}
},
+ "gh-6157-unnecessary-free-on-string.test.lua": {},
"gh-4077-iproto-execute-no-bind.test.lua": {},
"gh-6375-assert-on-unsupported-ext.test.lua": {},
"*": {
diff --git a/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
new file mode 100755
index 000000000..e2d25d7d4
--- /dev/null
+++ b/test/sql-tap/gh-6157-unnecessary-free-on-string.test.lua
@@ -0,0 +1,29 @@
+#!/usr/bin/env tarantool
+local test = require("sqltester")
+test:plan(1)
+
+--
+-- Make sure there is no assert due to an incorrectly set error in mem_copy().
+-- How this test works: We have 128 mempool cells in SQL ("lookaside"), and
+-- until those 128 cells are filled in, the error cannot be reproduced. Also, we
+-- have to get '' from somewhere because if we just enter it, it will be of type
+-- STATIC and no memory will be allocated.
+--
+local s = "NULLIF(SUBSTR('123', 1, 0), NULL)"
+for i = 1, 7 do s = s..', '..s end
+s = "SELECT "..s..', '.."NULLIF(SUBSTR('123', 1, 0), NULL)"
+-- The "s" variable contains 129 expressions.
+
+test:do_execsql_test(
+ "gh-6157", s, {
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
+ "", "", ""
+ })
+
+test:finish_test()
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